My '17 Denali has the Apple Car Play and to be honest, I don't think its worth it. Other than the "Neat" factor of having emails or text messages spoken to you via the sound system in the truck, there's not much else to it. I would say that about 75% of the features available can only be exercised when the truck is in park. I thought it would be cool to be able to play music from YouTube but it won't play it at all.
It says you can purchase extra features that access more 'Apple' things on it, but after some quick reading, most all of them are also 'non-operative' while the vehicle is moving. I don't sit in the truck and watch movies or videos or listen to the radio while parked, neither does my wife and I bought the truck for her. She gets in, puts her phone on the center console lid (which is a charging station) and off she goes. Plugging her phone into a power cord is a thing of the past
We used it once on a family trip, we got a kick out of listening to texts and emails but the new wore off of that before we got to the end of the block. I listened to Black Label Society thru it once and to me the sound quality sucked. I somewhat regret downloading all of those Metal tunes on my iPhone with the intent on using the car play feature. But since that one time we tried it out, we haven't used it since!
But, this is only my opinion and I'm sure there are others who use it more frequently. I would save the money and buy a new deck or put that money into a tune or a performance upgrade of some sort.
Chad