Google doesn't give your map collections to advertisers.
It's true that Google gets to see them, but Apple is no better in that regard: they store your collections on their servers too (where else would they store them?).
Maps keeps your personal data in sync across all your devices using end-to-end encryption. Your Significant Locations and collections are encrypted end-to-end so Apple cannot read them. And when you share your ETA with other Maps users, Apple can’t see your location.
Other useful sections on that page worth reading: "Location Fuzzing", "Random Identifiers", and "(on-device) Personalization"
That’s interesting. Can you point to a reference for that?
I would have assumed that shared collections with a group of iCloud accounts would be e2e encrypted like iMessage groups are e2e encrypted. Glad to revisit that assumption.
It's true that Google gets to see them, but Apple is no better in that regard: they store your collections on their servers too (where else would they store them?).