In my library [1], wrapping the CUDA APIs in modern C++, I do allocations which are not exactly from an arena, but something in that neighborhood - memory spaces on context on GPU devices.

Unlike the GP suggests, and like you suggest, I have indeed embraced RAII in the library - generally, not just w.r.t. memory allocation. I have not, however, replicated that idioms of the standard library. So, for example:

* My allocations are never typed.

* The allocation 'primitives' return a memory_region type - essentially a pointer and a size; I discourage the user from manipulating raw pointers.

* Instead of unique_ptr's, I encourage the use of unique_span's: owning, typed, lightweight-ish containers - like a fusion of std::span<T> and std::unique_ptr<T[]> .

I wonder if that might seem less annoying to GP.

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[1] : https://github.com/eyalroz/cuda-api-wrappers/