IMO, you are a better engineer if you understand how the abstraction works, at any layer of abstraction. You need to pick the point of diminishing returns for yourself, but I think it's pretty uncontroversial to say a developer that understands how a compiler works, and will dig around in a hex editor from time to time will be more knowledgeable and more likely to notice issues sooner than a developer that assumes the compiler is a magic hole in which to throw source code into and perfect executables pop out every time.

"But what about what runs the compiler! What about what runs the OS! What about the physics involved in electron transfer!" Diminishing returns I guess? No one's ever said you needed to understand everything, but understanding or at least being aware of a few layers under you seems to have been common sense forever. Taking one abstraction layer step up doesn't really change that.