why do people make these levels (Mario Maker 2 Super Expert)

I came back to super mario maker 2 for the first time in years and tried to play super expert endless. the levels on here are insanely hard especially the auto levels, speedrun levels, and any japanese levels. I managed to complete 2 difficult stages with one being a 10 second speed run. #mario #supermario #mariomaker2 #mariomaker #luigi #mariospeedrun #mariomakerlevels #toad #princesspeach