Yes, you can share location, the widgets aren't as fancy as Google integration with everything.
Not feasible without the constant data harvesting in the background, which it doesn't do. It doesn't log your every move as Google does. Privacy vs surveillance, will always be at odds.
Depending on the area. In my country public transportation is way better on OSM than on Gmaps. Oftentimes Gmaps won't even have large structures like train stations or bus terminals. It depends on users and contributors.

[–] explodicle@sh.itjust.works 4 points 2 months ago

It would be cool if there was an opt-in libre database to which we could submit pseudonymous traffic data. It would be hard to prevent sybil attacks though.