Pro CD players with Pitch controls?

I've seen these for years but never owned one. Anyone try these with good effect? Is pitch control the same as tone control? Do these types of players have anyplace in "high end" audio? It seems kind of interesting to be able to play around with tone without altering the key. (I've also seen CD trainer players that allow slowing down a recording without altering the pitch or key, but thats not what taking about now.) How about Pro DJ players - they seem to be build very rugged. I especially liked the looks of a two drawer Denon player made years ago. It had a real heavy industy look, which is something missing in todays products.
A friend who is a symphony cellist required this feature in her CD purchases. She uses it to fine-tune the pitch to that of her instrument, adjusting "on the fly" for variations among passages used to accompany her practice sessions. I recall she's ended up with several NAD's that incidentally had good audio qualities as well.