People need to stop being cheap and always pay for enough storage to have their phones and photos backed up at all time. They complain about paying for anything until they loose their data and then pretend they never knew.
it's not really a 'promotion'. it's a new feature. allowing you unlimited online storage space meant for backing-up (a qualified device) before repairs or when migrating its data to a new device. a new feature that mimics something apple already offers.
if it were a 'promotion', there'd be a way to buy or sub to that 'unlimited' space after a period of time to keep it going indefinitely.