I finally remembered the third point (which I'd forgotten in my post above) to be gained by Hillary's effort to carry the fight beyond the first ballot at the convention:

Many of the delegates are only bound to vote for a particular candidate on the first ballot; after that, those delegates may vote their own judgment. It is not uncommon for the whole picture to change on the second or third ballots, with delegates who are now freed from their initial obligation voting for a different candidate than the one they were required to vote for on the first ballot.

This is the point at which she could gain (if not the nomination) a great deal of negotiating leverage.

Dave Oesterreich