I do it for fun and lets me understand the platform more, I like tinkering and sqeezing all that I can out of my system, Although Nvidia, AMD and Intel kind of made it boring now, AMD got their PBO, so for example my 5800x boosts to 5.1ghz and a all core at 4.7ghz, all I did was allow 200mhz more to the PBO offsets and play with the voltage curve, thats it. Got my ram to 3866mhz but thats as far as I can go keeping infinity fabric 1 to 1 with memory speed.
The last CPU that I had fun overclocking was my FX8320, only because I was able to get over a 1ghz overclock and there was some settings that would give decent gains, it was fun, but not practical as it went from a 125 tdp to like a near 300 tdp, it was good at heating up my room, But I was able to get 5.1ghz out of the chip and it ran that way for years, I beat the snot out of that thing and its still going in another PC although stock.
The last GPU that I had fun overclocking just because it was different was the Vega 64, a higher core clock didn't mean you'd get more performance, it was a weird card, my 5700xt I did the power play mod and it idk, wasn't as fun, my 6800xt I'm still playing with it, got it to 2500mhz from its stock 2300mhz.
I do miss the old days where even a 6 mhz jump was a good note worthy jump lol