There doesn't appear to be good evidence that this is better for RSI. I found one study that shows greater shoulder and back strain when doing the hover hands approach. It might make more sense for piano since you need more mobility up and down the keyboard, but for typing your hands don't need to move nearly as much, so resting should be just fine. The do suggest some sort of support under your wrists, though.

https://pubmed.ncbi.nlm.nih.gov/15145291/