In more general terms, the eBPF VM goes out of it's way to not be Turing complete in order to solve it's version of the halting problem. Instruction stream graphs must be able to be translated to a acyclic graph by the verifier.
Yes, clearly. But it could be used in places where you want performance guarantees. Like, a client sends a custom sort function to a server to build responses, wide-open WA would not be appropriate for this but maybe a guaranteed acyclic control flow could work. Etc.
Sort is interesting because it's difficult to make a sort algorithm without unbounded loops. Although I guess a comparison function is probably easier, and leave the sort itself in the trusted computing base.
