I think you are kind of comparing apples and oranges. A decent UPS delivers voltage regulated wall power (smooth spikes and dips, or a brownout) and seamlessly switches over to battery power when wall power dips or drops. It often has a bunch of additional hardware that adds to the cost but wouldn't be useful to someone using a CPAP machine with it. Ex. remote access via Ethernet or at least a connector to signal a PC so that it can cleanly shut down.

I don't believe that power stations like the one you linked are designed to maintain power seamlessly during an outage. I recall it being a battery that you'd switch to if you lost power or to take camping. I don't think it's meant to be run plugged in all the time with devices drawing from it all the time. Admittedly, I have no power stations so maybe I'm not the best person to comment.