I'm not involved directly in any research using quantum dots/wells, so I don't feel I qualified to make that kind of prediction. However, the article shows the quantum dot the transistor was contained in, which looks like its an order of magnitude larger (70-80 atoms). It's one or two atoms out of 70 move, there isn't going to be nearly the change in properties compared to one or two in the seven that act as the gate. Computer components need to be able to last for years at or near room temperature, and I honestly can't see that happening for any structure at the 7 atom scale, ever. But I'm not a "nano" guy, so maybe these researchers know something I don't.

Yes, even in a crystalline structure. Diffusion in solids at the macroscopic scale seems slow compared to say, cream in your coffee, but at the atomic scale... They did this at the surface, which makes it even worse. I can't imagine this lasting any useful amount of time without some SEVERE cooling measures. I'm not sure if even liquid nitrogen could save it. IAAMS.