Bubble is a dryer. It has both functions of hand and hair dryers.
Considering people usually use paper to wipe the water off after washing hands which unconsciously wasted lots of papers.
Thus, the design combines both functions of hand and hair dryer for reducing the waste of papers.
Using the dryer is like pressing out the gas inside of the bubble.
Concerning human factors, the curve on the surface shows the place and holding way for user to hold it easily.