The redistribution is productive, because by redistributing risk (not just among people, but also across time), some ventures that were otherwise not feasible become feasible. For example, you want to build a house - but you don’t have the cash. A bank gives you a loan. They take the risk that you won’t pay them back, you get a house, and return they get a premium. This benefits many stakeholders (you, the bank, the builders, etc). If the bank has too much risk, they can off board it to someone with deeper pockets and a more diversified portfolio.