The objective is to make drawers strong enough, fast, and cost effective. In that order of importance.
Board lumber (other than general rough construction lumber) is expensive locally so it could be self eliminating over ply. There are no "real" lumber yards left around here. Just construction lumber yards who, "can get that for you, but it will be expensive." The last guy with tons of good stuff actually was across the street from my old office. About the same time I went over to see him about some stuff for a big job he retired and liquidated everything. He didn't have anything I needed left. Just my luck. LOL.
Not sure who made the comment about gluing end grain on plywood, but um... only half of the end is end grain.
One thing I noticed is a lot of the guys (on YouTube anyway) doing pocket joinery don't seem to be using glue. When I have glued and screwed ply in the past (not pocket joinery) I used lots of glue. The combination is pretty darn strong and doesn't seem to shift, tweak or flex much. Ply is also pretty stable.
By the way I do know what a box joint is, and I got the message about stacking the first time. Jim is more of a metal worker than a wood worker like myself. You are more likely to see him hanging around R.C.M than R.W