I'd love it if this were offered a la carte; in addition to, or instead of, a subscription. I could see not wanting to have a subscription for a pretty long time... but then here comes the family road trip and it would be worth it to me to plunk down $10 for a map update- Or if there was some fancy new driving mode, well I'd like to hear about it first, maybe watch a vid, then perhaps download a free trial? After 3 days I either have to delete it or pay for it.
But if it becomes another monthy bill that's just more $$ against you trying to sell them, on top of the payment and insurance. Not unlike looking at a house that comes with an HOA.