They're called "Ticket Alimentación", and they're provided by Edenred. They're electronic these days to prevent the easiest ways to convert them into real money.
Among the problems:
- most places don't accept it, so you HAVE to go to the places where they accept them. That sucks a lot (nowadays I can't go to the small local places as they don't have the infrastructure to process them, since government heavily monitors their use)
- you can only buy essentials with them, but that does not include stuff like paying rent.
- all taxes and stuff are taken from the "real" money, and you can have a negative "real" income while having too much in food vouchers (which can't be used to pay rent or utilities or transportation).
- you're basically forced to spend them (I make more than what I'd like to spend on food & essentials), you can't save unless you do some kind of hoarding or buy-to-sell scheme. I'm pretty sure some kind of black market would emerge where your proposed "necessity dollars" would be exchanged for "nicety dollars"
I don't have enough leverage to individually negotiate not getting paid in food vouchers, but it's definitely a factor I'm going to consider.
Thank you very much for posting this. I owe you.