I buy groceries at the same store each week, which has its own loyalty/voucher scheme, as is the norm here at least (UK).
Yeah I shop for various things in town, but I can't be bothered with vouchers for them.
I guess if you're a very promiscuous restaurant goer who lives in a city, then this could be useful for you, but it's hardly in the same ballpark as Google.
I suspect your spending habits are fairly unusual.