Silly question:

Does this broadcast button create some sort of event that ends up effectively spamming everyone's feed?

My assumption is that it's a tool to spread notes to newly added relays which may not have access to the notes yet:

https://image.nostr.build/af73cc4c8f1309b62fbd7a33e6529973656ecb33939bcaf69c479c9f8fd555a3.jpg 

 Test