In the lower right corner of the OctoPrint web page is "OctoPrint 1.4.0 running on OctoPi 0.17.0". Sure would be nice if " using Python " were added there.
I'm sure there are other places where the Python version would be useful.
Hm... I'd prefer to not have the footer grow even more but I'll think about something there. Come to think of it, that information will also probably become fairly crucial in the future, though it IS logged to octoprint.log.