Individual choice which often depends on the personality and attitude of the higher skilled player. I play down frequently. I enjoy being involved in bringing joy to people as they discover pickleball. I don't criticize others who don't enjoy the experience of playing down. If the higher skilled player is disappointed it often shows, and the lower skilled player ends up feeling badly. Both players have a miserable experience.
This morning I played at a venue where everyone was 3.5-4.0 except one woman who may have been a 3.0 (or lower). I was able to play with her a couple of times. She was a nervous wreck as you can imagine. My goal when playing with her was to make her laugh and not worry. One technique I find works well when a player is overwhelmed is to tell them every ball is for them to take. I act as a back up for the balls they can't reach. By telling my lower skilled partner to take whatever they can reach they have less things to worry about, and I almost always see an improvement in their play.