>>48755946he's tyranitar before tyranitar. sure the pokedex says he's a manlet, but in game he looks tall, imposing, and monstrous. he looks like he would eat godzilla for breakfast and mothra for lunch (in pokemon terms, he would. he has a type advantage over both ttar and volcarona afterall)
he's fucking cool. that purple/white color scheme still looks unique and is still rare to see in modern pokemon designs. while other anons are right it looks darker and muddier in earlier art (making him even more imposing), the brighter scheme today still looks really solid.
in gen one can use nearly all of the strongest moves in the game. two ohko moves, every good special move, earthquake, body slam, and hyper beam. to this day he still has one of the biggest movepools coverage wise and now wields one of the strongest offensive abilities in the game, sheer force.
in short: he looks fucking cool and is always a monster to use in-game and competitively (still UU to this day, though sadly NU in gen 1 due to unfair psychic dominance)