Attack and Defense seem to me to be some of the most important stats for fighters. For those who think Morale is more important
, experience also increases that, and Precision (and at 3-star, Strength). Not only does the Academy not cause casualties, it also doesn't cause afflictions. I think it's a great site to have, especially during peaceful times, and/or for troops on reserve. Not to mention that it can be used not just or plain troops, but on non-mindless uber units, to make them even more uber.
It's not Mount Chaining, but it is an appropriate and decent effect for those with the patience to use it, IMO.
PvK
Edit: Simply training up new troops to one star essentially makes them elite, and doesn't take very long or cost more gold than maintenance during the time they're training. It can also help impatient players maintain a prudent reserve force...