Heat is a big issue, but we are close to the physical limits of transistor size, they are nearly the size of atoms AFAIK. So this will allow us to have more of them closer I guess with no heat limits. There is also a lot of stuff that goes above my head about quantum tunneling when our transistors get that size. But transistors use semiconductors (Sillicon) not conductors, so this isn’t a drop in replacement. Will require a new type of transistor that uses a conductor I suppose.