I think this explains it
So you can probably share the button device but it sounds like HK wont send the push events back to HE, you can only program them for HK automations. I guess it is designed for a HK compatible button paired directly to HK where physical button presses or virtual would both run the same HK automations.
So yeah, easiest would be a virtual switch with an auto-off setting so it acts like a button. OR if you really want a "button" you could probably tie it to a virtual switch in HK, hide the switch and show only the button on your dashboard.