I really do wonder if it's sunken into the devs yet just how lucky they are.
This is pretty much the highest honor an indie character could possibly have, to be considered on the same level as Mario, Sonic, Ryu, Pac Man, Bowser, and so on. To be immortalized for generations. To have people fight and argue on the internet about your character returning for Smash 15 and how much they miss when they did 5% on the forward smash instead of 2%. To have your character be a skin or bonus in tons and tons of games as an Amiibo.
If Shovel Knight gets into Smash he'll be immortalized as a Smash character, forever. The same immortality that can keep an old race car driver relevant, or a forgotten Pokemon around, can breath new life into an old NES series, and introduce millions to a quirky, niche RPG series.