I'm not sure what you're talking about. It's a skill with limited usefulness that has real drawbacks. The comments seem well aware of that.
See especially the comments made by professional tuners (which matches what my own piano tuner tells me).
(Maybe that's less true for true perfect pitch, though.)
Imagine if, someone showed you a two and you just saw in your head what 2 + 1, 2+2, 2+3, 2+4 were intuitively. This would give you a leg up in elementary math (And beyond). This is similar to what relative pitched people experience. An absolute pitched person often just sees the two and if they see a three, the relationship between the two has to be learned.