You're welcome. It's a bit of a pet peeve of mine that people seem to be optimising the wrong things.

That said, to add another reason why doing the GPU ones may well be worthwhile on modern systems anyway, whether or not one addresses the other performance bits: Being able to use shaders to add effects is fun. E.g. I hacked in an (embarassingly bad) shader into Kitty at one point to add a crude glow effect around characters to make it usable with more translucent backgrounds. Doing that with a CPU based renderer on a modern resolution would definitely be too slow. I wish these terminals would focus more on exploring what new things doing GPU based rendering would allow.