I used to have a special running bike made by an unfortunately now defunct company in Australia (run4). They described using their bike as “running on air”. That’s what standing up to pedal feels like to me on a regular bike, and it’s especially pleasant when you get the gearing right. My Trek is now dialed in perfectly with the 52-tooth chainring (even though I had a slight glitch installing it).
I enjoy both zoning out for a couple of hours for a standing cruise and hitting standing intervals hard. “Stand-up pedalling” is now my favorite exercise. If I was allowed to do “real” running I’d probably be doing some of that, too, but “running on air” is a nice substitute.