Rust has constant by default, which many don't like in gamedev circles. Yes, compilers don't care and optimize - at the highest optimization setting, otherwise it's marginally slower, and each constant use will just add up.

Other Functional Programming features of Rust makes writing transform functions quite good, until you need to get the results of those functions to be displayed.

Some of the system-level allocation is quite hard with Rust, if not impossible.

The borrow checker is hard to use with games, not to mention it has a big impact on performance.

Object-Oriented Programming is possible through macros, but sometimes you need OOP instead of Entity Component System for more system-level stuff. Sure, ECS is really nice for game systems, but Bevy (an engine written in Rust) uses it for everything.