It's the cheer squad. Does nothing really to help the candidate, but makes the supporters feel good. There is also the off chance just the repetition of the name will subliminally affect an undecided voter.

Anecdote: Do you know of Marc Malon? He worked for Sara Gideon while she was Speaker, then Atty General Frey, and a former Chair of the York County Dems. He hates yard signs, thinks they're useless and was vocal about it. When he announced that he was running to succeed Ryan Fecteau in the House, he acknowledged the irony that now he has to get yard signs made for himself even though everyone knew he'd be unopposed.