The web frameworks look interesting too, but I haven't deep dived those just yet. You really get a Rubylike language with native performance which is very interesting.
One thing I wanted out of Nim is slightly more Python-likeness, I want regular OOP, since Crystal takes from Ruby (I believe it was originally written in Ruby, before it became self-hosting) it has sane OOP features I miss when I use Go, Rust or even Nim.
I really feel in a different timeline, Crystal could have been something, I also feel like "Ruby" for some leaves a bad taste, but Ruby is nowhere near as awful as most people think, even though it was never for me, it was still one of the nicest ecosystems I ever worked with long before Go got its package management situation situated.
Edit one more thought: I believe the Windows installer / Windows support for Crystal is a newer addition if I'm not mistaken, so it took a while before it got proper Windows support. Well, I just googled it, it started in 2023... but still, that's fairly recent by my book. I think any programming language should strive to work across the "big three" as soon as possible to increase adoption. Go took off the moment it came out for Windows and was formally released.