EVO is kind of the golden standard for all fighting games. When they legalized custom moves, a majority of tournaments followed suit (besides CEO & some Houston tournaments). If Smash 4 is removed from the EVO line-up, the Smash 4 scene will begin to fade, & this is my biggest concern. The Melee scene won't give up their EVO slot, Smash 4 is the newest kid on the block that is actually getting support from Nintendo, & many are complaining about there being 2 Smash games (despite the two being completely different). Plus DLC can only keep a game alive for so long (see Injustice). Hell, there are still channels that barely cover Smash 4 at all (GRSmash, a popular YouTube channel that basically compiles Top 10 moments from the Smash scene).
And For Glory isn't exactly the best representation of tournament play (5min instead of 6, no customs, no Mii Fighters, Omega only, etc.), though I don't think that was the point of your post.