Will an arts supplement help for BS admissions?

Just a reminder that it’s just my opinion so feel free to do what feels right for you. Another way to look at it is that I personally believe exact same information shouldn’t be repeated in an application — so if you play trombone in the band and you play as well as that sounds on paper, then sending an OK submission is just repeat information which just dilutes the power of the more stellar parts of the application. (And if the trombone sample is just OK, I’m going guess that there are more special things to highlight so why distract?)
Hope that helps.
Again so what feels right for you.