Some games are more demanding than others so no GPU is really a "60+ fps GPU"; even within a single game you may be lucky not to see the occasional dips in frame-rate during particularly demanding battles etc.
Put another way; when you buy a powerful GPU, you're not doing so to get a frame-rate faster than the human eye can perceive, you're doing it to guarantee that you get a good frame-rate the entire time.
If a GPU can average 80 fps at a game, then you know you'll rarely (if ever) dip below 60, or you can use the extra headroom to enable fancier graphics settings, your preference. Many games are locked to avoid exceeding 60 fps now anyway, as extra frames don't really do anything except waste power and generate heat, so it's usually better to run the GPU a little less hard.
Short answer; no, it's not a waste 😉