That is also a legit way to look at this. I just don't think it helps anyone. If you only have a 3DS and are ok with not sharing your levels, maybe go for it. If you already own the Wii U version DON'T WASTE YOUR MONEY.
The issue there is that it isn't just the "making" part of the game that's severely handicapped. They've fucked up the "playing levels" portion enough that I don't even think you need the context of playing the Wii U version to be bummed about it. The platforming mechanics are obviously great, but you're given fuck all to do with them, so it can only do so much to salvage the game. Those challenge levels are
not of the quality of a standard Nintendo-made Mario platformer (As much as anybody wants to make it out to be "like a full-fledged Mario platformer," it is not), and many of them are either taken from the Wii U version or remakes of older levels in the series (sometimes both). To suggest that those levels are anything more than a curio is severely overstating their value.
And then the Internet functionality makes you wonder why they even bothered having any in the first place. You can't upload courses. You can't download courses. You can't look for courses. You can't star courses. If you liked a level you played, you can't do anything about it to get more levels like it, or even see the other levels that author may have made. If there was a level made that happens to have a mystery mushroom in it (which is pretty common), you are never even seeing those.
These aren't just luxuries that can only be afforded by a Wii U. Many of these things are fundamental concepts that have no reason to be absent. This game is the worst-case scenario everybody imagined the Wii U version could be before it was released, and the Wii U version existing doesn't excuse
any of that. To suggest otherwise is insulting.