I keep feeling that SMB3's star has grown to be the most senile and pointless recommendation in the history of TASVideos. Most of the movie time is dedicated to autoscrollers (which don't really change for the better over time), and there are nearly no new tricks compared to Genisto's 6 year old version that would be obvious to newcomers. All the improvements that have happened since then are marginal and esoteric enough to need particular explanation on why and how they're faster. Read
this submission text if you don't believe me, and note the amount of frames saved by subpixel management, bankable savings, luck manipulation, lag reduction, and so on.
At the same time, pretty much everybody who takes interest in TASes has either watched one of the SMB3 TASes prior to browsing the site, or watches it among the first movies. If they don't like, or haven't played, SMB3 in the first place, I don't think it goes too far to make the experience appreciable.
SMB2 is a
much better candidate in my opinion, no matter warped or warpless. It's no less optimized, but the glitches feel more fresh and unusual than anything seen in SMB3.