[kllrnohj]

> Thinking that only "embedded" cares about custom allocators is just naive.

I said absolutely no such thing? In my $dayjob working on graphics I, too, have used custom allocators for various things, primarily in C++ though, not Rust. But that in no way makes the default of a global allocator wrong, and often those custom allocators have specialized constraints that you can exploit with custom containers, too, so it's not like you'd be reaching for the stdlib versions probably anyway.