"Willingly" might be overstating things - Google is expert at misleading privacy notifications, and just like they wouldn't expect the local baker to keep logs of what they buy and when, and sell them to data collectors, maybe they have a naive idea that buying something on their phone is similar. They're just not aware how deeply hostile and backstabbing the entities they're dealing with are - like most humans, they're adapted to dealing with neighbors and people they know, not amoral international conglomerates.