Note also that Finest Detail is required to preserve detail in 360ppi files when printed to roll media (it's not required for sheets). Why there would be a difference is a mystery to me.
Which printers, which versions of the drivers, and what evidence do you have for this?
Finest Detail is designed to deal with perfectly straight lines, such as you would find in vector output, along with the sharp edge contrast. Most photographs, even of straight edges, aren't purely straight or such complete contrast as you have with vector art. The 720 mode is designed for the type of output you would expect from vectors and may not provide an improvement in other printing. You might get some benefit, but generally unless you have that much resolution natively, any opportunity for improvement will be lost in the upsampling process and you just have larger files that take longer to print.
For large native resolutions files, as Schewe said, it makes sense to send it through and take advantage of it.