shyt was a cartoon that had nikkas fighting, explosions, fatality like deaths and the protagonists and antagonists would one up each other with power-ups often so there was always something to talk about. also, the animation was good for them times. the shyt just stood out from the other cookie-cutter cartoons we had on tv back then, and now nostalgia and memories works on its favor
there's really no hidden rocket science behind its popularity
but yeah man, vegeta sacrificing himself vs majin buu was a real nikka moment and everybody i knew back then talked about it for days/weeks