Is it possible to use a virtual presence sensor in a routine?
Sure! - Why not?
The when “Someone arrives…” trigger should work just fine if your Virtual Presence instance is correctly defined and triggered.
I use a virtual presence sensor to change the behaviour of my smart lighting routines when we have visitors to stay. So my “do things when everyone leaves” rule, which kicks in when all registered phones are no longer present, also includes this virtual presence sensor, and the rule will not run when someone else is here and I’ve toggled it on.
I’ve had no issues with it.