Honestly, I struggle to use the welcome drink voucher. Usually when I check into the hotel, it's already late and I want to just settle my stuff in the room, then get out into town for the evening. I usually wind up on my last morning thinking 'oh m**** I need to use up my drink voucher before I check-out, let me just get a cappuccino before I leave.
But then again, I don't travel for business so perhaps the scheduling is different from you guys.