They're more convenient than sending a note or a message through a third party, even if that third party can move through the castle almost instantaneously. Plus, we can have conversations with a group of people.
I took a room on the third floor overlooking the Quidditch pitch, though it's more of an overgrown field now. Madame Hooch would be horrified.
I talked to Nick, and he said something about wizards trying to use Muggle science to help make more wizards. He was vague on details, but that would line up with the Baron, minus the bigotry.