About two years ago, from 2080ti to 4080. Nothing nvidia makes is "worth it" but I do use it a lot on a 77" 4k OLED TV and pretty much all games I play run quite well with all the goodies turned on (which includes DLSS, usually Quality, and framegen sometimes which can let me run DLAA), so in that sense I at least get some good mileage out of it.
My power bill is not great..
I'd love to develop a muscle memory for working with it, but nowhere I've worked uses it at all. But from memory it really wasn't that complicated, and the errors it spat out into system logs basically told you exactly what command to run to get past that particular violation.
I don't hate it at all. Just, never seen it used anywhere.