Only a minority actively participates. But it's for all the other reasons you mention yes.
And, unrelatedly, even though few actively participate that isn't the point. It is a motivational vehicle. And I repeatedly hear about this from folks who join and don't participate. That's perfectly fine with me.
It's hard to keep people active for this kind of initiatives. I am also running an engineering book club and found the same challenges, especially with timezones. However, as soon as you find a group that can join every week at the same time over Zoom, it's the best way to build community and enjoy the discussions.
And, unrelatedly, even though few actively participate that isn't the point. It is a motivational vehicle. And I repeatedly hear about this from folks who join and don't participate. That's perfectly fine with me.