Not at all a game changer, for me.
I mean, it’s just another and one more type of cable. Sure, in theory it’s simpler than many various cables and it’s even less stupid than the previous USB types, but it’s still a mess.
At least, for non-geek me, those cables are a mess as I need to be able to distinguish between the exact same cable to find which one is USB-C or Thunderbolt, between the various versions of USB-C itself, and then between USB-C that comes with or without power delivery, and with what power limitation? And then, despite USB-C supposedly being a standard there are still too many cables that just won’t work with certain devices because reasons.
Add to that the many USB-C docks (and dongles) that work… more or less reliably and more or less as marketed (even more so under Linux, but those issues exist under Mac and under Windows as well).
Older cables and ports were cumbersome, and thick and whatever but, as far as I’m concerned, for the most part they just worked like they were supposed to. And I never had an issue knowing which cable to plug into which port as they all looked, you know, different.
Nowadays, I have to label each one of my USB-C cable with some masking tape so I can identify it in a glimpse without wasting my time trying them all one by one.
Edit: some clarifications.