It depends if you're solving for quantity or quality. If your goal is to get the highest volume of traffic possible, then it sounds like search isn't going to be your primary channel, and targeting broader audiences on social media might be a better option.

However, if your goal is to get qualified leads, it may be worth going after those long-tail keywords (more specific, lower search volume) - you'll likely pay a lot less for them in Adwords, and the folks who do search for those keywords will be a much closer fit for your business.

SEO is much more than just keyword rankings. Good SEO focuses on the bigger aspect of web marketing which is about driving traffic from all online sources, using keywords, social media, links, content, etc. There is also the usability and conversion avenues that web marketers should be helping you improve as well.

The goal is to drive as much converting traffic to the site as possible. SEO can do that by focusing not on high-traffic keywords, but high-profit keywords. It doesn't always take a lot. But beyond that you want to make sure your site can convert the traffic it is getting. By focusing on usability issues you make a better site experience for every visitor, regardless of how they found your site.

If your site is focused on providing great value for a particular audience, then your website should have great content and a good website structure that is user friendly. If this is the case, then search engines will find your website and include your information in their search results.

I would spend some money on an SEO consultant to make sure the structure of your website is optimized for search engines.

A PPC campaign doesn't make sense if you don't have specific keyword to target, unless using a display campaign.

I have many different sites that don't focus on one particular keyword, these sites receive thousands of search engine referals from all sorts of search terms.
My sites include directories, news publications, product catalogs and informational websites. For all these websites Organic search is the number 1 referrer of traffic.

So, yes SEO is a good choice, but you may not need a continuos campaign, just someone to get the structure correct in the beginning.

Many people have the misconception that SEO means ranking keywords on Google. That's not the right concept. SEO means Search Engine Optimization. It about optimizing your website for search engines. Ranking keywords is just 1% of the overall game.

I think you should focus on branding and inbound marketing rather than on SEO or PPC alone.

I wrote about it in my book, "NO SEO FOREVER".

If you want to talk more about it, I am always here to help you out.

Short answer, no. Not worth it.

Focus on generating profitable leads.

If however you're still hell bent on going the SEO route, focus on profitable and high converting keywords. How does one do that? By doing a PPC campaign and then watching which keywords convert. Then do SEO based on keywords with buying intent.

Far too many times I have seen people spend a lot of money on keywords that get a lot of traffic but have very little buying intent or conversions. It's not about how much traffic you get, it's about how much quality targeted traffic that converts.

It's difficult to provide a definitive answer without knowing the niche, but if you know PPC will work (which is keyword based) organic SEO should be more cost effective long term. Also, if search volumes are low, organic results should be easy to achieve and therefore less expensive.

I've run into the same problem in the past and been shocked about the amount of keywords I had never considered that drive traffic.

Primary keywords are often head tern keywords, which show up most often in the Google Keyword Planner. Google leans towards showing high volume, commercial intent keywords. They do show a lot of informational keywords, and keywords with 10 searches a month, yes, but they are predisposed towards keywords that AdWords bidders would want to bid on. So keep in mind when using that tool who Google's customers are.

I believe it is most likely worth the effort because if you're seeing not a ton of volume for your keywords, it's possible that your competitors saw the same and might have decided it wasn't worth focusing on SEO for as well. That could be your opportunity. It depends on your monetization strategy and your industry. If there were only 10 searches a month for "how to make an easter basket" and that's your industry, it would be tough to make a strong case for spending a lot of time and money on that. If there are 10 searches a month for "oil field exploration companies" then each one of those people represents millions of dollars of revenue.

So in order for you to decide if it's worth it, you have to know what industry you're in and the volume of your keywords and keyword value.

Here's an experiment you should do to see if it's worth it. Take your top 10 primary keywords, and write one page of content on each, at least 1,200 words of content either in the form of a blog post or a service page. Put your best effort into it, and imagine your target market is already visiting that page. Wait 30 days and check on those pages in Google's Search Console. More than likely you'll see those pages bringing in traffic for keywords you had no idea people were using to find your site. Or on the flip side, maybe there's just no demand there. Either way, this will give you an early indication of whether it's worth it or not without you having to make a big expensive decision.

Happy to answer any followup questions!