I think that is old advice and I hope it's on its way out of golf instruction.
Bounce is glide and forgiveness. My lob wedge has 22° of bounce and I trust it more than anything from the firmest of lies.
It's bogus to say, IMO, that you want less bounce for situations. Plus, the same course can have firm areas, soft areas, etc. Bounce is forgiveness.
Plus, a lot of the clubs with less bounce have wider soles, which limits flexibility.