Clever interfaces are attractive, I'll give you that.
There's an element of discovery, a little surprise, may be even a pinch of delight, if it matches user expectations.
The cost of cleverness
But cleverness brings with it layering and cognitive load. Most times, this means complexity, which the average user translates to hard to use.
When you hire a designer to build an interface, your expectation might be that of looking at an exquisite design, never before seen, that will stand out and steal the world's attention. Critics will be dumb-founded at the originality, onlookers will stare at it for hours, and you'll be smug thinking, it was you who did it, you hired the designer after all.
This line of thinking has just one major problem; clarity trumps cleverness, and if you try to be too clever, users will loath you.
Designers like clever
Designers do have a tendency to do clever things. This could be born out of the an urge for originality, or making things prettier, but at the end of the day, usability demands clarity, not cleverness. If you are looking to make things usable, you'll be aiming for simplicity.
Clarity begets speed and efficiency
Clarity means that the user will do their job faster, with minimal errors. This translates to efficiency. If your business wants to keep users engaged, it's probably a good idea to make their lives easier and give them efficient ways of doing things.
Keep cleverness for power users
Power users need a lot of flexibility in their work, that's primarily why they're called power users. For them, it makes sense to think of clever ways to design interfaces. Their work is complex, with lots of options, scenarios and use-cases. Meet their complexity with cleverness if you can.