Perfecto Mobile is for testers that won't probably see the code, for example. They have access to devices that have the app/apps. From there, they will create automated scripts that will then perform almost the same thing as UI automation. The thing is that with UI Automation, you have to give accessibility to your elements in order to test something. I would say that UI Automation has a better performance overall. Think of it in this way:
UI Automation - Developers or persons that will have a closer relationship with the code.
Perfecto Mobile - Testers, that sometimes don't even know how iOS works internally. This is useful when you want to really separate things: developers develop, and testers test it.
Separating things is good, because a tester that never seen code, or how the app is suppose to work, gives a fresh perspective to the project. You can also argue that, normally, a tester ( a person that tests for living) will do a better job a testing than a developer.