Besides, if they're charging a fee for it, that means the hardware ships as part of the car, which means you're paying for the cost of the hardware in the purchase price of the car already. You're just not getting to use it.
This subscribe-to-use seems absurd to me too, but you can imagine the reasoning.
At some point it becomes cheaper to manufacture all cars with the same hardware rather than, say, 40% with heated seats and 60% without*, not to mention dealers having to balance stock of different options.
That's done, next you have the problem of activating the purchased features for any particular car. You're not going to have hackable switches or necessarily trust the dealer to only give their customers what they paid for, so a request has to go back to BMW for an activation key for features X, Y and Z, and the customer pays it.
But these features are expensive and customers skimp on them. Let's lower the cost by making them subscription, then customers will sign up for more and hopefully forget about it and keep paying.
Frankly the main annoyance I have with this is the mental load of managing yet another financial relationship and ongoing choice. I just want to buy a car and use it, not micromanage it. Nor do I want to subscribe to a fridge, washing machine or any other life necessity that should be set-and-forget. Just stop.
* I'm reminded of the scientific calculators we had in school. The cheap model had the same board as the expensive one but no holes or buttons for certain advanced functions. Interpid students could cut holes in the case to upgrade.