Now that tuples are Equatable, using == will now always prefer the Equatable implementation. In a sense, now that newer binaries won't be compiled against this == function, it will eventually deprecate itself (we still have to support so that older clients can call it however.)
This is a very important question, and I agree with your evaluation behind which magical conformances we should provide. I've only suggested Codable because it's been mentioned a number of times before, but since there's no current precedent perhaps we should hold off.
Aside that's relevant to conversation: It's also important to state that we shouldn't wait for all of these magical conformances before working on proper implementations. This proposal does, however, allow newer conformances to be added fairly easily, but each conformance should be carefully considered.