It isn't an ego thing, it is a consistency thing. People go mad about getting higher end grinders, machines, etc... because they are trying to control for all possible variables. Espresso is incredibly finicky about those variables, but you can control for them with the right equipment.
It is pretty easy to demonstrate that the higher end burr grinders have greater adjustability and consistency than the lower end ones. It is also totally obvious that they are needed on any higher end machine.
I used to think it was all bullshit too, then I got a Silvia, started with a blade grinder, then a low end burr grinder, then a rocky before I could finally get the grind both fine and consistent enough to pull a proper shot.
It isn't a subtle difference between a good shot or a bad one, anybody can tell the difference.