I think the difference for me is that the importance of communication for solo programming is a bit of a sliding scale depending on what your goals are. There aren't many exceptions when you work on a team. When I use the word importance, I'm tying it to a notion of necessity in relation to some goal. Team goals trump individual goals in organizations.

if you have no intention of making your code available for someone else to read / use / modify, the benefit for having readable code is really for yourself in six months and nobody else.

you also don't need to tell anyone what you're doing, so being able to clearly / succinctly explain what it is and why it's useful isn't a necessity. Does that make it an unimportant skill? No, it's just that the goals are different