I try to argue with myself pretty frequently. In fact, some days I don’t even have to try.
It’s good practice! If I have a particular opinion, insight, or plan of action then my mind will sort of automatically drift to counter-arguments for that position. I’ll try to talk myself into a different viewpoint.
The beauty of this happening in side my own head is that there’s no outside social pressure. I can be very genuinely “on both sides” of any view because I’m not trying to impress a tribe or gain status. I’m trying to be real, and correct. I can steel-man the argument on both sides and come to better conclusions.
It also makes me pretty well-prepared to debate any of these topics in real life, should the need arise. If I have to explain myself, I’m prepared to do so.