Why is transferring ownership before payment so dangerous?

Most subcontractors don't realize they're giving away ownership before getting paid and keeping all of the risk. So many contracts in the clauses, they will say that the ownership shifts on delivery of the good or the service that you've provided, not on payments. So for an example, the client damages the materials, the subcontractor has to replace it. The way that you fix this is that you want to have the risk transfers on delivery, but ownership transfer is on payment. That way you can maintain the ownership of the thing and you can take it back unless they pay you. But you know, you don't wanna get in a situation where you've given them and they claim ownership and you still haven't been paid for it. Obviously that doesn't make sense, but that's what the contracts you are signing are saying.