Why should she even suspend her campaign? She can keep campaigning the delegates. She should say she is “returning to her office to do the people’s work.” (gag)
"Suspend" is a term of art. It just means that she's not going to be publicly active.
Entering "suspended" status is significantly different from conceding defeat, at least it is in a race as close and contested as the DEM primary is. The race isn't officially over until the delegates cast irrevocable votes.