The radio, Apple CarPlay and Android Auto has been a subscription model since the 2019 models I believe. Why not make every feature a subscription then?
I don't think this is like SiriusXM at all. For example these are builtin features such as heated seats. You have to pay a subscription to enable the built in feature to your car in order to use it. No third party subscriptions required.
They can install whatever, I promise if someone purchases a Beamer with subscription heated seats there Will be aftermarket mods that you can install to make them turn on and off without an app. This is more for the people that will be buying (or especially leasing) a new BMW who are already paying a monthly fee for a package of extras.
BMW Is Planning to Sell Heated Seats and More as a Subscription (No, Really)