I think the previous replies cover the topic of 1:72 figures well. I’ve used them for a bunch of side-projects, where I wanted to give a period a try but didn’t want to go all-in on 28mm. For me, that has been samurai, Colonials, WW1, WW2 and War or 1812/Napoleonics. Only the WW1, WW2 and War of 1812 projects really went anywhere, but I’ve been quite happy with the results.
I don’t really understand why, but I can paint 1:72 figures to a decent standard far more quickly than 15mm. Faster than 28mm, I understand, but 15s? I think maybe it is because the 1:72 figs are so cheap that I don’t get as uptight.
In any case, the finished armies look good and you can make big units without going bankrupt! My War of 1812 infantry are 32-man units and they look suitably imposing on the table!