I guess they would already have had that authority?

I think it would be the ongoing job of the dean's or at least someone to be setting graduation requirements? Why would the trustees have to explicitly delegate it?

I think this was more of a press release than an edict. The Purdue announcement says, "Built on recently launched AI majors, minors and certificates across colleges, and following the establishment of a working group last summer, with additional careful deliberation and advice from the University Senate through its Undergraduate Curriculum Council..."