The BT offer will appeal to some. Probably members with low balances as DC Freeloader points out. I have a fairly strong balance, enough for a trip across the pond in style (if you get my drift) and I would certainly rather blow 12000 points this way than €600 in vouchers for shopping (I hate shopping). Flights to JFK around St Patricks Day are currently priced at €2k. Flights next month to ORD are priced on some days at €4,800. At these prices, it is a no brainer for me personally.
As an aside, I see EI are again advertising biz flights for €699 each way. This is a great price for those lucky enough to be able to afford it.