It depends on what you are cooking, but I usually do. Maillard and caramelization reactions will not occur in the temperatures that your pressure cooker will get to. If there's an option to add those flavors to a meal, I'm going to do it. There are cuisines, though, where that's not traditional or desired.
Think about rice, for example. Sometimes, you want more delicate fluffy plain white rice, while other times you want to do a pilaf technique where you brown it first. Neither is "better", just different.
Generally, if an ingredient is susceptible to overcooking, I'm not going to pressure cook it. Rice is easy since the grain size is consistent, but something like chicken breasts, I'm not going to pressure cook.
Adding more high temp cooking will drive out more moisture, but sometimes that's worth it. I would never eat a steak without a search, for example.