It's actually not that common. Players will use chess engines to analyze positions, but they will rarely play against them because it doesn't provide realistic practice for an actual chess match.
For example, it may be reasonable to play an aggressive variation against an opponent because you think they might have difficulty finding a response in time pressure, but a computer can make precise calculations in any situation, and so such a strategy almost always backfires.
What's more, chess is often abstracted at higher levels in terms of things like long term plans ("I want to put pressure on the c7 pawn and control c6") instead of concrete material gains, which allows players to make progress even in positions where there are no direct threats and no sensible exchanges of pieces. Computers when faced with such situations will know that the position is objectively drawn and so will just shuffle their pieces around aimlessly, and playing against this kind of thing is not very good practice for actual human opponents who will try to find ways to beat you anyway.
Only realistic if they were preparing for some sort of Man vs Computer tournament.
Computers don't play like humans, and they are consistent in their weaknesses as well as their strengths. As players are more exposed to playing against various chess programs, they learn what positions computers are not so good at (long-range strategical themes, beyond the typical move horizon). A local optimisation, of sorts.
So players start adopting an anti-computer style of play, which requires a different mind set to pull off. That in turn affects their natural style of play.
So I argue the opposite, for preparing for top-flight tournaments, players probably avoid / severely limit playing against chess engines, to avoid this natural anti-computer bias to their play.
Sure, the engines are good for checking variations and analysis, as an assistant. But not as a leader, nor as an opponent.
