As an example, if Patreon allowed Creators to connect their Stripe accounts and allowing the money to go directly there.
Is there a risk, if it came to "returns"? Making the company liable and not necessary having the money to cover some costs?
Or is it just to control the money flows?
Also, again in some countries, your tax authority may decide the person is actually your employee and not just a freelance contractor. Again, extreme, but a risk if you are paying the same person on a regular basis.
Paying via a third party platform usually absolves you of such hazards.