Developers who don't have regular physical access to a Mac.

My use case might be too specific. But, at home I have a Windows Desktop and Laptop. In the office I use a Mac Mini. Currently, I need to test Apple Pay for Safari. This requires test iCloud credentials. On a mac, this is difficult or prohibitive to swap between live iCloud and test iCloud logins. On Windows, testing via browser emulation is shaky at best.

Also, easily sharing access to a "cloud" (read: remote) instance of macOS with other developer staff is beneficial.