Unfortunately, yes, having celebrities perform helps a candidate get votes. Our country is quite obsessed with celebrities, and if they see that their "idol" is supporting a particular candidate, then it may swing their vote in favor of whoever the celebrity is supporting. Personally, it does not affect my vote, as I believe celebrities are just there for entertainment.
There are multiple reasons why performances by celebrities can help influence votes. One is because people tend to look up to the musicians that they listen to. Another is because they might tune in to hear their favorite musicians, and then hear a little more about the candidates they have to choose from.
Could any American please tell me why there is so many celebrities involved? Can you not understand what's going on unless it comes out of a celebs mouth? The whole election is an embarrassment and neither candidate is fit to run what is essentially the free world. Anyone else notice that the Democratic VP is a huge no show last night? Looks Like Hillary did concert after concert...
Performances by big celebrities like Bruce Springsteen do not help a candidate get votes, they are just for show biz and to make the campaign rallies colorful. Voting is driven by ideologies and how well candidates sell their policies. In as much we may want to believe that such celebrities support the candidates, they are paid to perform so it is actually not true that they influence voting.