If you have a smartphone, it can be tempting or "productive" (the air quotes are probably reasonable!) to do non-driving things while you're driving, if you're the sort of person who's tempted to do that when you have a smartphone available. I think this is largely orthogonal to whether or not you have CarPlay.
I'm guilty of being that sort of person occasionally. I've found that having CarPlay in my new car reduces the temptation to do "non-driving things," because the things that I do that are related to driving -- navigation apps, streaming music, and for me, playing podcasts -- become easier to do with CarPlay's UX than with just using the phone in a holder like I did in my last car. The screen in my car is much bigger, the touch targets are bigger, the UI is simplified, the design encourages me to use voice input. (In your example of changing to a different playlist, I can just press the Siri button -- which perhaps amusingly in this discussion, is a physical button on my Insight's steering wheel! -- and say "Play [name of playlist].")
I'm guilty of being that sort of person occasionally. I've found that having CarPlay in my new car reduces the temptation to do "non-driving things," because the things that I do that are related to driving -- navigation apps, streaming music, and for me, playing podcasts -- become easier to do with CarPlay's UX than with just using the phone in a holder like I did in my last car. The screen in my car is much bigger, the touch targets are bigger, the UI is simplified, the design encourages me to use voice input. (In your example of changing to a different playlist, I can just press the Siri button -- which perhaps amusingly in this discussion, is a physical button on my Insight's steering wheel! -- and say "Play [name of playlist].")