Not entirely related, but a friend of mine that does competitive DDR uses baby powder on their pad to decrease friction (so they can move more quickly/efficiently). I imagine they're also trying to achieve some ideal balance of grippy vs slippery. I think my piano tech would probably murder me if I baby powdered my keys though.
Weightlifters, gymnasts, dancers, and boulderers of course often use chalk for grip... and now I can't stop imagining a pianist chalking their fingers before a performance ๐