I echo your thinking on having a starndard chain to use across several saws, that certainly adds a lot of value to your sawing activities, and hence your questioning the value of the picco bar/chain setup. And it makes perfect sense to me why you run the saws that you have described.
My expectation is that the narrow bar has a smaller surface area for the chain to run on, so there is slightly less drag/friction between the bar and chain than with wider bars, and the narrower chain has to cut less width of wood in the "cut", so it requires less power to cut through a log compared to a wider chain/bar. Hence giving some logic to the "performance" and "appeal" of the 241 that we read about.
I don't have any proof of the difference in cutting performance of different bar/chain widths with comparison testing, but I am sure someone here on this forum has done some testing...
Whether it is significant or marginal, I don't know..., but any potential benefit of the narrow bar/chain is likely to be much less in operational value than the "shared chain" advantage that you describe in your post.