> it always baffles me that most people seem to be using Rust to write ... web services?

I think it's the whole x-rewritten-in-rust-now-faster hype train. Although those limitations you mention, what's easy and hard to do, do have a more or less automatic impact on performance, fueling that train.

I think of it like this:

Programmer level 1: Makes something work in a higher level language

Programmer level 2: Makes something work in a lower level language

Programmer level 3: Makes something fast in a lower level language (in most cases just a few simple optimisations on top of #2)

Programmer level 4: Makes something fast in a higher level language (object pooling, understanding how the GC and VM works to avoid GC pauses at the wrong time and all that)

So with Rust (or yes, C++, though it's a bit more of a foot gun IMHO), level 2/3 people can write code that's efficient. What I think is somewhat unique about Rust is that it keeps programmers from making lots of common mistakes working with lower level languages - like it's designed for level 1/2 folks.