That's true. C++ templates are exactly like that too.
They are a bit arcane though, and many developers are afraid of them and use them very conservatively or even avoid them altogether so maybe this helps mitigate the issue.
Comptime (at least with the language I'm currently working on) are a lot less scary, and people use them quite a lot without thinking too much, so maybe it's the main difference. And I think Zig is closer to this than it is to C++ templates, but I can't be sure since I've never seen people writing Zig code.
Edit: it's late in here, and I completely missed your point. I'm personally not usually afraid with language features, but some requires more work than others to be accustomed to, and not everyone is willing to spend their spare time doing so.
There is a lot of templatized c++ library code out there, yet in everyday practice I find it's very rare that I need to instantiate a template with a type that causes a compile error.