To be honest, it's just what I've been using since I switched to Cachy half a year ago. There was no conscious decision made between yay or paru.
I think Go and Rust are both great languages, but there are apparently some speed benefits from using rust/paru. That's not anything I can factually confirm, just what I've heard.
I love my razr 2024, but I've been patiently waiting for graphene to support a decent non-google phone. Looks like I'm about to get the best of both worlds!