I thought this might interest people on this sub forum.
In my opinion, Shopify themes (both paid and free) cannot create truly engaging user experience due to outdated tooling developers need to fight against. Just check this site built with modern tooling (Next js instead of liquid templates) and experience the difference yourself.
FYI, I haven't made this store nor am I affiliated with their devs in any shape or form. In fact, its "FREE", you should know a bit about coding though to customize it yourself. This is where you can get it from https://github.com/vercel/commerce.
Shopify themes can be fast but they cannot offer instantaneous page loads like the site above because that is just not how liquid templates work.
I need to mention a big caveat though. You cannot use apps with such sites, so its a trade-off you need to consider. You will need to hire devs to extend the functionality of your site if you go this route.
Headless e-commerce is definitely the way to go if you want to try and make your website as performant as possible. While you can optimize standard Shopify sites to be quite fast, you can only go so far since you don't have 100% control over all of your code.
There are definitely some pros and cons to going down this route but could be a really good solution for the right business.
The fact that you can build a site with modern tooling like Next.js/Gatsby/etc. and just pull shop info in via Shopify's API is an awesome way to unlock next-level performance. Like you mentioned though, this means you'll have to give up or rebuild all of your app functionality, it'll take longer to build, and you'll need experienced developers to build and maintain it.
If the business has the budget for it, this could be a really great solution to help them stand out. Definitely an interesting topic and I'm excited to see how headless e-commerce progresses over the next few years.
After working on large-scale systems using Next.js over the last years, I'm always curious about headless e-commerce solutions.
My personal impression is that there's currently a huge push for headless e-commerce and plays really nicely with Shopify. In its current state it makes perfect sense to start out with liquid, the provided themes and some apps, as it's the most efficient way to get started. Then, if a store generates enough sales, uses many apps and the whole system reaches a more or less "stable" state, comes a point where a next.js storefront really begins to shine.
Luckily, there are a ton of tools, themes and app-like modules popping up for such solutions. With the eco-system getting more mature we will probably be able to use headless solutions much earlier in a store's lifetime. I'm looking forward to it!