Those things need to be paired to be able to see each other's data stream so I assume it's encrypted.

Also there are almost certainly TWO big breaker boxes (one for each appartment) plus meters - all of which with coils, which filter out high frequency signals - between your network and your neighbours', so your bandwidth is not going to be suffering from neighbours that are using a similar system, unlike with anything radio-based like Wi-Fi.

I actually suspect this is even better suited for appartments than for standalone dwellings when your objective is bandwidth, because the signal will basically stop at the breaker box so you don't really interfere with each other whilst with Wi-Fi what stops interference is distance (and big thick walls or large metal surfaces) so appartment buildings are pretty nightmarish for it because everybody is so near everybody else.

My own personal experience with this is all in appartment buildings and I actually first tried it back in the day when everybody and their dog started getting Wi-Fi and routers had become smart enough to automatically search for a less constrained Wi-Fi channel on setup (before that they all just used a default channel, so for a few years manually reconfiguring my router to use a different channel other than default would put me in a clean area of the spectrum few neighbours used) because Wi-Fi bandwidth by then had become was so bad whenliving in an appartment because of ther being so many people with their own networks in such close proximity.