Just give me money so I can spend it how I want to, free perks at work aren't actually free
Naively, yes. But if they gave you the $X to spend however you want, you'd have to pay income taxes out of it and then sales taxes to buy for yourself. When the workplace does it, they don't -- and it's an expense for them! Plus, they get the bulk price.
In which case let the employees decide what to spend things on
If they did it that way, it would be taxable income.
Kind of shows the difference in worlds between plain old tech (sushi as motivation for a half hour survey) vs gaming (food as incentive/etc. for ridiculous hours)