Often times when I see public figures on media having multiple microphones during their speeches. Sometimes even up to 5 microphones for one person at a time.
Why is this? What are these microphones used for?
There are a few possible reasons. If you see just two identical mics it's for coverage and diversity -- to get a good signal no matter where the speaker faces, to shape the pickup pattern.
If you see multiple different mics it's usually because the venue didn't provide a 'gang box', a splitter that can supply feeds to many different sources, or one or more of the people being fed couldn't connect to it.
Another (more cynical) reason is that many news organizations want to place their logos in the shot.