So there are some (like Cooper) who feel that the "best interface is no interface"... claiming that "No UI" is about the user and making things easier. They quote Don Norman and Kevin Ashton with quotes like:
“If we had computers that knew everything there was to know about things—using data they gathered without any help from us—we would be able to track and count everything, and greatly reduce waste, loss and cost.”
After holding up Nest thermostats and Trunk Club as poster children, you might say that they are making sense. Except "No UI" doesn't do away with the UI. These are learning systems that require less touching as your relationship with the product continues. What they're missing is that these products still have a UI.
Timo Arnall did a great piece on why the whole "No UI" movement is silly, but I'll go a step further. Claiming that one way of interface design is better than another is, sadly, a trap that people on messageboards and at conferences use to rile people up! What's the best interface? IT DEPENDS! It depends on the client, their target audience, levels of complexity desired from said audience, education level of users, and so much more... it's pretty much impossible to definitively say what might work best witout having other criteria to base your judgements upon.
In the end, "No UI" being the 'best' or 'wave of the future' is just as much bullshit as the skeuomorphism vs flat design arguement. Tread lightly when engaging in water cooler talks, fellow designers!