Same with teachers, usually.
"Staging" in your ambulance for an entire 24 hour shift. Fuck your comfort. Not on a call? You can hang out in the rig. But not in the back.
Oh, when I said 24 hour shift, you can be mandatorily "held over" for 12 hours if your replacement is sick/calls out.
Oh, when I said up to 36 hour shift, the last private EMS company I was at allowed shifts of up to 60 hours, at which point you could be assigned to another shift after 8 hours break.
But at least that means a good amount of overtime. Shame EMTs often make around $10-11/hr in a lot of places (if that).
It's not healthy for patients, and there's a few reasons why it's "tolerated" (not agreeing with these) - "We always have done it this way", and around here, being a unionized city/county fire-paramedic is the top tier for income, and around here, there's few enough paramedic schools that several of them have minimum EMT field experience in time or patient contact numbers, so it's considered a grind until you can get through. And EMS companies know that because of that, there's a steady pipeline of young people willing to "go through the wringer".
But that mechanism would make absolutely no sense for people working out in the field.
For facilities that use these apps: are these the only game in town? Where are we on the slope to nurses in a region having no other way to get shifts?
Why is it that nurses are down there with, maybe below, teachers? Perhaps because they are not expected to have a long-term relationship with their customer.