The $100 million warchest belongs to the Biden/Harris campaign, not the Democratic Party. They are separate organizations, and Biden/Harris only answers to Biden and Harris.
The DNC has its own funds of course, but nowhere near as much. And DNC funds are supposed to be shared with multiple Democrats, not just the one running for president.
Maybe, but then the swing state could end up with a GOP governor. That’s one reason why VPs are often from safe seats, eg Harris, Pence, Biden, Palin, Quayle…