Due to hand problems of various sorts and generally being trash at the pacing of most traditional fighters, I can confidently say that without Smash I'd be almost completely out of the genre.
There's a lot of character designs and story elements in fighting games that I do enjoy, and I even took a crack at a couple, but I just couldn't bring myself to a point of competence where I'd bother with anything but, like, maybe a story mode. And I'd probably eschew it altogether in favor of other types of games that scratch that itch better.
Smash just clicks with me in a way other fighters don't, even when I'm taking it seriously. The increased emphasis on movement and decreased emphasis on precise, convoluted inputs or long combo strings somehow kinda flows better in my mind than a traditional 2D layout does.
Bust most importantly, if Smash didn't exist, I wouldn't be here talking to you about this.
And honestly that's the biggest loss, cause you're aight.