I've had one for a few years. In my 70's now and living in a hilly area. I use my own leg power for 90% of my journeys but the power assist (6 levels) means I can get up hills I would either struggle or simply not be able to tackle. Also when going through the town I can boost speed to avoid creating to much an antagonism. My bike also has a "moped" switch so, when totally knackered, the bike will take me home.
Good e-bikes cost "2K-£3K, I bought a "normal" commuter bike for £500 then bought a conversion kit for another £500. Cost me £100 to have it fitted. The wiring is a little untidy but that doesn't bother me.
I ride for about 1-2 hours three or 4 times a week. Keeps me fit without risking a heart attack.
Only down side are a select few pathetic motorists whose paranoia often put your life at risk.