One other problem with Smartcubes is that it stops the time the moment you solve the cube. On a lot of puzzles you could then learn how to quickly do U4 or something similar so that you wouldn't have to recognize the AUF. Predicting AUF for EG on 2x2 is something that takes time to learn and might immediately become obsolete.
On a more abstract level, I think that recognizing that you have completed a solve is a very important part of solving the cube, even though we usually don't think about it in this way. If the time stops immediately when you get an AUF skip, it seems weird that the time stops before you even realize that you've completed your solve. A more egregious case could be if the cube reaches a solved state in 3BLD, but you had incorrect memo so you end up flipping an edge unnecessarily, etc. It would clearly go against the spirit of the event to count this as a 3BLD success.
Even if many of these problems could eventually be dealt with, overall there are a lot of drawbacks and the only "problem" this seems to solve is that pickup times could be removed from the solve time.