As a huge band, it probably gets a bit monotonous to perform the same songs day after day, so it makes sense to change it up a bit and perform something a little different for the hoards of fans. Many bands have payed tribute to Prince over the years and although they are never going to live up to the icon himself, it's usually pretty decent. Howvever, some bands just shouldn't even attempt to take on such a legend because shit just gets embarassing, like this recent performance from Metallica.
The heavy metal band decided to perform Prince's legendary song
When Doves Cry at their latest gig in Minneapolis and I've honestly never heard such dogshit in my life. Take a look:
As you can see, James Hetfield and Lars Ulrich decided didn't join in because they clearly had more sense. So what you're left with are Rob Trujillo on vocals and bass and Kirk Hammett on guitar. It's just proper cringe. Stick to headbanging, lads.