Bosman doesn't want the pressure/association of Patreon for his show. Anyone could technically steal it and upload it anywhere, but that would just be a dick thing to do.
The Game Sleuth alliance channel is to benefit EZA with wider exposure, and the deal (contract?) would presumably be so that they would post the free version (non-patroen early version) on that channel first so EZA couldn't upload it onto their channel.
The exposure is worth it (assuming it's a big channel), and BTW the Youtube ad revenue EZA would get is so small it's not worth mentioning.