uhhh, just check the description for the link

its easier to make characters with a limited moveset and smaller sprites making it so that lazy devs (like me) can create a character. its also fairly new so naturally you'd expect some devs to jump in the bandwagon. there still are some regular characters being pumped out (but yea i guess ssl chars do kinda cover them).
if you are interested more on ssl chars, check the discord server:
https://discord.gg/Bexse4Vv8f

also
it's its own game mode and it's easier to make characters

yo tuckerphelps07, if you don't want my wrastor, play base cast wrastor.
its literally right in the game.

tuckerphelps07 This is style is cool too

okay why is everyone making characters in the style of SSL, it just like their just done with making cool characters.

blaziken

:O