Why do medical device companies hire clinical practitioners?

Clinical practitioners are practitioners! Let's say you're a doctor at a hospital! There is a piece of equipment your hospital wants to purchase! They have! And you're working part-time for them or something, do you think it's going to work out? Let's take a step back! You don't have a job, you have a license! But you have a license means that your classmates ah ex-colleagues are doctors have it! Then this thing you sell or reliable