Generally, I would say hard pass on a feature like this. Most single-player games represent a series of challenges to overcome, with an escalating level of difficulty that is ideally tuned to provide a sense of accomplishment when overcome.
Static difficulty gives you a clear bar to cross and makes the sense of accomplishment more tangible, as you keep improving your performance relative to the goal.
If the goal shifts (with dynamically changing difficulty), you could lose that. I would say games that use level-scaling are guilty of this at some level. In that case, the satisfaction from numerical Stat-based progression is attenuated by the dynamic scaling.
That being said, difficulty is also a pacing mechanism, and I can imagine situations where you might use some sort of dynamic difficulty system to enforce the intended pacing / feel of a game. I think this is tricky and has lots of pit-falls, but it would be cool to see experimentation around this in my opinion.