I wonder why a router is really useful to them. With most sites using https, not much beyond DNS requests and plain IPs can be captured, without forcing users to install a CA.
Agreed, but don't minimize the value of logging all DNS requests. You can get an unbelievable amount of deeply personal information from having a list of every DNS lookup. As an experiment, fire up a pi-hole and look at the logs of your own requests. There will likely be a lot of info in there you wouldn't want public.