Back in the 90s, Sonic ONLY got popular due to the coolness factor. SoA always tried to make fun of Nintendo and be the "cooler", more "adult" option. Sonic is shit, the games have poor design where you just keep running until you hit something, or learn the stage inside and out so that it actually becomes playable.
Same with Mortal Kombat. First game ONLY got famous for all the blood and gore, not because it had better gameplay than Street Fighter or Fatal Fury.
It's also very telling that neither Sonic nor Mortal Kombat ever got popular in Japan. Only in the west where people think it's more important to be seen as "cool" than to enjoy a fun game.