I vaguely remember we used the XOR trick on processors other than Intel, so it may not be Intel-specific.

In principle, sub requires 4 steps:

1. Move both operands to the ALU

2. Invert second operand (twos complement convert)

3. Add (which internally is just XOR plus carry propagate)

4. Move result to proper result register.

This is absolutely not how modern processors do it in practice; there are many shortcuts, but at least with pure XOR you don't need twos complement conversion or carry propagation.

Source: Wrote microcode at work a million years ago when designing a GPU.