My knees like the support of E-bikes, after having argued against them for more than a decade for similar reasons to yours.

I also take them when I am exhausted, since I can tune in some support if I need it.

My friend with MS does use her E-bike and when that isn't possible her electrical wheelchair.

I use the bike even for hilly and steep routes since then I can add a bit power

I have more control over when I get to some points, meaning that I ride the bike more (since I can add/reduce the power that is supplied by the motor)

long trecks and tours are much easier with a group of five when everyone got E-bikes (as long as no wheel gets hurt). In our case that involved kids who we normally had to curate routes for very well. Now we have an ease of use that wasn't there before.

the overall product quality of the E-bike is higher and that means it is much easier to ride and the components do last longer than what I would've bought instead. The maintenance though is slightly more expensive.

driving in cities is much less a problem since I am not angry having to stop in front of signals and also getting speed is much faster, meaning I can cut a few minutes from most distances

transporting heavy things is actually much easier (this includes material from shops, food, but also bike trailers for kids

I feel much more save with E-bikes next to cars. For various reasons, one is that the base speed I got is good and when I use a short muscle power burst I can get the 28-33km/h that are at tempo 30 zones usual. Couldn't ride that speed the whole distance though.

I just use the bike much more than my non E-bike during similar times and get more distance covered with it.