I don't play any online competitive games or FPSes, but I can definitely tell that 144 FPS on a synced monitor is nicer than 60 FPS, especially when I play anything that uses mouse look.
For me, it's not quite as big of a jump as, say, when we went from SD to HD TV, but it's still a big enough leap that I don't consider it gimmicky.
Gaming in 4K, on the other hand, I don't really care for. QHD is plenty, but I do find 4K makes for slightly nicer desktop use.
Edit: I'll add that I almost always limit FPS anyway because my GPU turns into a jet engine under high load and I hate fan noise, but that's a different problem.
For me, it's not quite as big of a jump as, say, when we went from SD to HD TV, but it's still a big enough leap that I don't consider it gimmicky.
Gaming in 4K, on the other hand, I don't really care for. QHD is plenty, but I do find 4K makes for slightly nicer desktop use.
Edit: I'll add that I almost always limit FPS anyway because my GPU turns into a jet engine under high load and I hate fan noise, but that's a different problem.