This gets posted occasionally and while I agree, the subscription for an airbag is one of the dumbest things ever, it's not the only way to buy the thing.
It's available as a one-time purchase instead, which obviously is what everyone here would choose, but it's a fairly high price, and their argument for offering a subscription model is that they want the price barrier for safety equipment to be lower. There are other ways to do it, but the option of a subscription is fine IMO as long as the one time purchase remains as well.