One or two guys in my coaching circle have done this in recent years. One of these teams has racked up a bundle of titles, but I don't think that the charting has been the specific key to his success. It seems to me that the charting is part of this coach's bigger blueprint. He (or she) wants everybody engaged on match day even if they don't have matches to play.
There is value in charting for sure. I think it gives the player being charted some empirical evidence of what's working or not working in a given setting. Very handy when reviewing the ups and downs after finishing a match. Knowledge is power.
But I also think the process of charting very much helps the teammate charting the match with building awareness of what's happening on the court and when it's happening. When high school kids can sharpen their situational awareness, they can usually play smarter and steadier and also be less prone to gambling with low-percentage shots that rack up the errors. Without even playing a match it can help a player (the one doing the charting) with learning to manage the X's and O's.
I've only used it here and there - not routinely - but on a couple of occasions in recent seasons my players have asked a pal to chart a match for them. Sometimes the charting might not even record all the action of a match. A player might just want their serves charted to get a picture of what sort of placement and percentages are happening through their service games.