I remember when the 3ds version first came out there was a good amount of tournaments going on and what not. is there still such A scene? i love the 3ds version and i think it deserves the same exposure as the wii u (imo) i personally don't see why the community have to be separate or there has to be one version over the other at tournaments seeing as both games use the same engine. Also, my apologies if this has been discussed on this forum a lot. I just don't see why this game isn't taken as seriously as the other.
Well then again, concerning the Wii U's poor sales, I would easily assume the 3DS version sold much more than it's counterpart considering Nintendo's high profit from the 3DS. Unless, of course, Smashers were their persistent selves and bought Wii Us just to play Smash Wii U. Then again, I'd do that given the opportunity.
If someone was hosting and streaming Smash 4 tournaments, you might as well use the version with better graphics and controls and with a better stage list; all that and being easier to stream. Though having played the 3DS version, it's only logical that you would use that experience from that game and translate it onto the Wii U since, like you said...
seeing as both games use the same engine.
So like it matters however you played Smash 4. It's not like Melee whereas a Gamecube controller would be the best and only choice for incredible tech play. Smash 4 has got to be the 2nd least technical Smash game out there (1st being Brawl), so like using a Gamecube Controller makes for that big of a difference if the 3DS version is handle-able at the very least and perfectly fine at the very best.
You never know. Maybe the 3DS version is played just as much as the Wii U, both casually and competitively, but the Wii U version is just streamed more often for reasonable motivations.