Nothing, he has to do with political connections, and OpenAI's main utility to Microsoft is as hand puppet for lobbying for the terms it wants for the AI marketplace in the name of OpenAI's nominal "safety" mission.
Easy. AI discourse has gone insane, on both sides, and is sorely in need of perspective from grounded, normal adults with a track record of moderation and shooting down BS. Summers is a grounded, normal adult with a track record of moderation and shooting down BS. Ergo, he's immanently relevant to AI.
He's also financially literate enough to know that it's poor form release market-moving news right before the exchanges close a Friday. They could have waited an hour.
Being financially literate means being able to understand how the financial system works. Larry Summers thinks operate as intermediaries lending out deposits. This is very wrong. He is not financially literate. He is an economist.
I think Larry Summers probably knows what a central bank is.
But "how money creation works" isn't the same thing as "how the financial system works". I guess the financial system mostly works over ACH.
We can see what happens when banks don't lend out deposits, because that's basically what caused SVB to fail. So by the contrapositive, they aren't really operating then.