profit "emerges" from money cirulating
vouchers don't circulate, you get payed in vouchers locked to you person (not transferable) , vouchers are created by performing labour and destroyed by spending it. It's more like a movie ticket.
This is manly done to avoid black markets.
You might say that profit is a bit like a hiden tax you pay but don't get any representation. So in the voucher system, you will have to pay lots of taxes, those are however visible and hence you can get representation. Basically you still have surplus extraction but people get a say in what happens with it, through various democratic means. You'll get more for your work because the current rulers are wasting the surplus they extract from you on lots of pointless stuff that don't matter to you, like their luxury they won't share with you, or playing games of thrones but with big military spending on pointless wars, Also no more gambling on wall-street.
There's an economic planer that will work out with computers what would usually happen in markets to be able to set prices. The system will be proactive, instead of markets that are reactive. That will spare us economic crisis.
Labor costs will be higher because people are payed in full, meaning there is a greater incentive to apply new technology quickly and at scale. because the main driver of technology is reducing labor cost.
