Epstein created a virtuous cycle of social capital for himself by MIT accepting his donation. While it was anonymous to outsiders, the insiders all knew.
For the tech crowd here familiar with venture capital, it would be like one of the top branded VC's being the first money in to your startup. It's a strong positive signal to others.
This NYTimes article has plenty of detail:
https://www.nytimes.com/2019/07/13/nyregion/jeffrey-epstein-...