It can also depend on the variety of alfafla, some are better for grazing than the hay types. Hay types tend to be stemmy because theyre bred for max tonnage. Its not as picky on fertility as some might think, but it doesnt like wet feet and does use alot of P&K.
I agree that for most part and for food plots especially, RR alfalfa is a waste, its already halfway RR anyway. But there are some situations where it is beneficial, I know to the north of me in the Sandhills, they love it because sandburs are a problem in hay fields up there and while you can spray Rup on non RR alfalfa and 9 times out of 10 not do much more than stunt it a bit, that 10th time youll end up killing it on accident.
If youve got plenty of food plots all year round and they arent keeping it mowed down, you could take a cutting once it flowers and then let it grow back, the protein will go up and it will have new tender shoots. It could help offset the cost of things, and otherwise it will get kinda rank and deer wont eat it. We just seeded 85 acres of irrigated alfafla this spring, put out 24lb/ac and I think seed was $2.50/lb??