There are lots of psych 'urgent cares' in our state. They are not privately owned, but there clearly is a large number of patients who want to be seen same day at a place other than an ER. One can find reasons to think that they should either be in actual ERs or just go back to their PCPs but for whatever reason it's a very attractive option for patients. Most patients have anxiety. They come in, are assessed, receive psychoeducation, care coordination, and if a follow up is secured may be started on medications recognizing that most psychiatric medications that are reasonable to start in this setting aren't particularly effective for crisis stabilization. I believe one way these settings are helpful is that it provides a low cost environment for brief containment so patients can regress to a less acute mean in a few hours and feel safe to return home and engage in regular outpatient care.
I don't see it being viable from a private practice perspective at all, as we have a nurse, a tech, and ability to get labs etc like most medical urgent cares.