You are providing the illusion of trust though.
There are a multitude of components between my app and your service. You have secured one of them arguably the least important. But you can't provide any guarantees over say your API server that my requests are going through. Or your networking stack which someone e.g. a government could MITM.
I don't know anything about "secure enclaves" but I assume that this part is sorted out. It should be possible to use http with it I imagine. If not, yeah it is totally dumb from a conceptual standpoint.