It could get quite confusing ... a band's name is meant to identify them. If there are 6 different bands with the same name, this gets even more difficult.
But I mean, I don't have any problems figuring out the difference between Ben Nichols' band and the hispanic pop singer.
Like you said, a band's name is meant to identify them. So forcing a band to change that identity after six years seems a little rude. If you don't like the confusion that arose, why not change your name? It's not like you can argue that picking the name "Discovery" for your band is something another band couldnt have independently done on their own.