As someone with a 2023 Chevrolet Silverado, I can honestly say that if my truck did not have CarPlay, I wouldn't have purchased it. As it is right now, I do not pay for the data plan for my truck, therefore the Google Maps (which is the only navigation built in to the system) just shows a blank screen. I can not use voice commands to send text messages, change the XM station, control the climate, etc. All disabled because I won't pay for a montly/yearly subscription. CarPlay is the only thing that makes it bearable as an entertainment system in my truck. Without it, it's just a big, useless screen.
This is the reason they want to exclude CarPlay. They want to force people into their subscription plan. Fortunately, I believe they will walk this back as it has become an issue with the recent Colorado / Canyon release. They are pricing in 3 years of service on the sticker of the GMC but not on the Chevy. From what I have read on general truck forums, you can request a reimbursement for the GMC after purchase.