If anything, I think the terms for this are almost too good. You never end up paying more than the cost of purchasing the device outright if you decide to keep the device. And considering it can have a term of up to 30 months (24 month lease, with 6 months more before you're charged the remaining cost of the device), you've just gotten a zero percent interest loan for 30 months. That's actually cheaper than buying it outright at the start of the term due to inflation. I seriously cannot see a downside to this program on the consumer's end if they end up keeping the device.

If the customer is the sort of person that upgrades yearly then it reduces hassle: no extra effort for valuing a trade-in or selling to a third party. It affects these customers the most because they might be able to recoup more in a third party sale in exchange for effort on their part.