Yes it is but you can get cheap insurance, just like you would get for a motor scooter or a car.

Yes, although I try to take precautions to prevent or catch it. For shopping I carry two u-locks and a wheel wire for my loaner ebike, and on my personal dutch-style non-e bike I rely on the built-in lock and chain.

Out of the several years I've owned my personal bike, there has been one attempted theft (they made off with my light, action cam, and bike computer) and that was during an hour long shopping close to midnight.

Look into whether your area has secure bike parking, such as within train stations with key card access, maybe ones attached to your local authority's office, or even run by any local bike charity of some sort.

I personally have left my loaner ebike locked up in train station keycard storage overnight while visiting another city, there are cameras everywhere which is reassuring, and the bike was untouched when I returned for it. On a separate occasion I left some of my clothing on the locked up ebike to dry, and they were exactly how I left them when I came back to ride home.

Nowadays I just try my best not to use general public access bike parking lol

Edit: should also mention that I keep all my bikes indoors now when at home. Last time I kept my old one out, cats kept pissing on & scratching the wheels, and it rusted so badly