These sorts of services do seem very dependent on the details of how they are organized.

I’ve had experience with two university libraries with 3d printers. They both advertise them similarly, and they were nominally similar services, ostensibly letting students and staff both 3d print and learn about 3d printing.

At one, the arrangement was that they’d show you around the machines, give you a link to a list of notes and rules, and then you could come in and use the printers. If you wanted to do something unusual or use an exorbitant amount of filament, they asked that you talk to them first. That service is what initially introduced me to 3d printing.

At the other, the library staff decided they’d rather handle everything themselves. You’d submit an stl, then they’d print it at some point, potentially weeks later. Random color pla only, no slicing and providing gcode or even requests for settings. In practice staff decided they would only accept links to popular stls online; submitting your own stl would be rejected. They printed at such bad settings that everything would come out horribly. The service was worse than useless, taught nothing, and may well have turned many students off 3d printing entirely, if they thought the results were indicative of what 3d printing could do. We essentially have to warn students that the service is not practically usable.

But both, of course, say they have 3d printers.