I demoed one a couple of years ago. It was a Trek, so a pretty nice one. That one had a small screen and a thumb switch on the right handlebar. You selected your level of power assist, 1-5 I recall. At 1, when you started pedalling, you could sort of feel a little extra speed kick in, but you still had work to do to get it moving. At 5, it was ludicrous. Say you want to climb a hill. You pedal like you're having a leisurely ride in a park, and the bike will power you up the hill like magic.
Your range will be heavily impacted at the higher setting, but used sparingly on hills, it will get you where you're going within reason.
I used to not like them, but I see the point. For one, you can have bike touring operations and explore mountains without hyperventilating. You can commute without breaking a sweat, as discussed. A lesser rider can keep up with a group of better riders for the social aspect of riding.
On the downside, they are *heavy*. The motor and batteries make handling awkward, but the variable pedal-assist nature of them means you get as much of a workout as you want.
They are also expensive, but so are bikes in general. I'm actually surprised that they are not much more than other high end bikes.
I would not buy one. Not yet. If my wife wanted to ride and keep up with my daughter and I, we would get one for her. We would just abandon Zach for an hour. Give him a screen and a couple of granola bars and we should be good.