It depends on how you use your truck. Yes, it is nice to be able to remote start it from anywhere with cel services since factory remote starters don't work inside buildings like hockey arenas, stadiums, etc. It's nice to see your trucks oil life, tire pressure, etc, get navigation routes sent to your truck before you even get into the truck, etc.
But if you tow, and your truck has the advanced trailering app, the remote access brings a couple nice touches. First, you can start the trailer light test from the app when you are standing behind the trailer. Second, if you are staying overnight somewhere, and someone goes to steal the trailer, as soon as the wiring plug is disconnected from your truck, you can set up the app so it texts your phone immediately to warn you someone is trying to steal your trailer. If you don't have the remote access plan, then the truck will set off the horns and lights, but you have to be within hearing range and realize it's your truck.
If you had the remote access on a previous truck, you can sometimes complain to the onstar rep, say you'd take it for $5/mth, and they will sometimes come back with a reduced offer. Here in Canada, I know people paying around the $7-8/mth for it if they had the remote access for 5 yrs free on their previous vehicle. Also, if you pay for the entire year or two (whatever your contract is for), they give you some months free. Example, if you buy a 12 month plan and pay for it all at once instead of monthly, you pay for 10 mths and get 12 (so 2 mths for free).