Pole calculation -180 not +180 phase
The big reason for preferring -180 is: feedback control for causal systems. In causal systems, only delays are possible which correspond to a minus-signed phase shift.

In non-causal systems, which can respond to "future" data, it is perfectly sensible to be able to have positive-signed phase shifts. This is possible whenever data is not time dependent. E.g. You have an image and your feedback control system is a filter operating on that image.