[kccqzy]

Any pure code (WASM or otherwise) that does not perform any input/output is by definition useless. It consumes electricity to do computation and there is no way to communicate its results.

The use case here was to use a KDF function from the TEE, and I assume it serves as an oracle where the actual key material cannot be revealed.

[gf000]

Turing machines have a well-defined input, and output if they halt.

So no, they are absolutely not useless, they are just "single-shot" models of computation. Certain software fit that model very nicely (e.g. compilers), others less so.