Ok, let me give an explanation of this whole thing. Super smash bros ultimate has almost every character in the Mario universe, and even beyond that! Everyone….. except for Waluigi.

Mario, Luigi, and even Wario have been in a mainline game, but Waluigi isn’t despite the fact that he is also an Italian plumber and even partners with Wario. They all have their own game series, Mario with Mario bros series, Luigi with Luigi’s Mansion series, and Wario with Wario ware series, but not Waluigi. He is in the Mario Party series, the Mario Kart series, and the others that didn’t really become as constant, but never anywhere else. Super Smash Bros Ultimate is a spin-off series, but Waluigi never appears. (Except as an assist trophy and probably as a Luigi reskin)
If you sign, we get one step closer to getting Waluigi into smash, one step closer to getting glory for Waluigi, one step closer to a great team getting together again, and one step closer to a complete smash roster!