Yes they might cushion your knees and joints from the blows associated with your foot landing on pavement but that’s a different effect that saying the spring action is actually helping you run more efficiently (like prosthetic blades do).
If a more recent record is accurately measured, then that's entirely fair isn't it? It seems like you're implying that an old record was inaccurately measured to be slower than it really was, and then beaten by a more accurately measured modern record?
Inaccuracy goes both ways, less accuracy could just as easily lead to a better time than a worse one.
The engine matters so much more and running. Yeah, 1 to 2% of advantage at the high end. It makes a huge difference for a metals.
But if you're in any sort of participatory level don't bother
Why not? You only live once. Might as well try all the things you can try and do all the things you can do. Who knows? Maybe the psychological impact of having supershoes will make you a faster, better runner.