"Why do they want to create a phone?"
They want manufacturers to produce high end phones that has processing power enough to run a full desktop OS.
When docked to a monitor, keyboard and mouse, Ubuntu Edge can run a full desktop, not just a scaled up phone OS. If you have thinclient access it can even run MS Office and business applications:http://www.youtube.com/watch?v=EtNhlVn3ETQ&t=3m4s
"Focus on providing an efficient phone/tablet OS that really brings something new and manufacturers will use it for their devices."
They have a OS that brings something new to the marked. Ubuntu Touch:http://www.youtube.com/watch?v=i-PEWGwk03o