It's an internal system that exposes implementation details all over the place, so I understand why they do it that way. You have to know a staggering amount about the architecture of macOS to use it correctly. This isn't a reasonable expectation to have of developers, hence why the formal sandbox API is exposed via a set of permissions you request and the low level SBPL is for exceptions, sandboxing OS internals and various other special cases.

Is AI a special case? Maybe! I have some ideas about how to do AI sandboxing in a way that works more with the grain of macOS, though god knows when I'll find the time for it!