There is nothing wrong to use this feature. I also used this for several times in history.
However, changing match time without providing reasonable time and notice for opposite team manager to react is unfair to him/her.
In my opinion, the old requirement that match time should be changed 1 day before is very reasonable. I don't like but accept if it reduces to 12 hours. Allowing managers to change match time 3 minutes before is not reasonable.
This feature is not very commonly used. Otherwise, I will immediately quit to play.