As a developer working with Rails (and previously Django), I'd love to try Phoenix/Elixir now. I'd probably find lots of great reasons why it's the best choice. And I won't be wrong.

As an entrepreneur however, I would opt for Wordpress unless there's a clear, strong reason not to. I know it's a bit heretic here on HN, and I dislike PHP and working with Wordpress isn't fun at all. But they take the concept of "Batteries included" to the next level. It's like "Nuclear power included".

You want a simple and powerful admin backend? got it. Caching? check. Image optimization? Yup. Logins? of course. Payment/Shopping Cart/Even subscriptions - just get woocommerce. 5 minutes later you're charging credit cards or paypal. Not to mention how easy it is to create content pages, landing pages, blog posts... You know, the stuff that actually convinces people to even consider your shiny new app.