I built my own blog in Elixir/Phoenix when I was looking for a job as a junior dev, and at that time it indicated to employers that I can learn a new language on my own, that I understand basic web dev, etc. Now that I'm more on the hiring side of the equation I would still be impressed if a fresh CS or bootcamp grad built a blog (or any other simple project) in a newer stack that doesn't yet have hand-holding tutorials.

However, outside of junior level positions, I don't think there's much you can glean from whether somebody has done trivial side projects or not. Obviously an ambitious side project is worth a lot, but the bar for building one is really high and there are so many great devs who can't reasonably make the time outside of work to do that.