The entire reason that's even a thing is because some people thought that doing things the Civ V way isn't good enough for a new game. The point isn't merely to win - it's to have fun. For some people, that's winning as fast as possible. For me, it's finding many ways to arrange an economy; or finding power or tech interactions.
I didn't like that they removed Generator play hard, but Specialists being good (without great people) is one alternative way to play. Experience brings informed ideas, and if we "balance" a new enjoyable way to play, it creates a richer game. That's how these games evolve.
As a result of play, it becomes obvious that some things are better than others and how they play - tile outputs all being buffed by latter game tech, virtues, and agreements means that in order to keep up, a play for a Specialist economy using Student Aid has to compensate with more yield.
Right now, only Barre can do that. As you mentioned, Food conversion is more convenient, and it's superior to what are effectively 4 food tiles from expensive buildings. However, with Barre, they're 6 food tiles; 6 food, 2 energy with the right virtue. That's competitive. Science is 2 Food, 5 Science, 2 energy. Still competitive, though it's obvious there that the Growers need buffing - they should probably be upped to 3 food, so even normal Civs on Student Aid can use the slots for growing! In all these cases, the notable limitation vis a vis other kinds of Econ arrangements is the need for specialist buildings, and they each have a tile cap.
Engineer slots are 2 hammers - effectively 2 food 2 hammers on Student Aid. It's a horrible tile. They're good for early game - not bad for extra production, but a late game Specialist economy needs a little more oomph. A hard internal TR focus with agreements and virtues and traits will generate far more. And conversion will prioritize tiles values and TR outputs. Barre's is 2 food, 4 hammers. Not bad, but completely horrible compared to Scientists.