Of course the search interface is alarming and undesirable.
If you're "searching for content" that's one thing. If you're _browsing_ for content, you want to be able to use your mouse and nothing else. You want your other hand propping up your chin, or holding a drink, or scratching your crotch, or whatever else is going on.
People don't want to type shit. Many everyday coomputer users hate typing. They're bad it. Slow. Uncomfortable. Switching between clicking and typing for many people is a slow process, a heavy-weight context switch that is unpleasant. They want to click, and only click, and switch to typing only when they really really really need to and they plan on doing a lot of it.
This is why people keep making shitloads of unmanageable bookmarks in their browsers, or dropping a bazillion links on their desktops. It has _nothing_ to do with trying to find recent documents which Zeitgeist supposedly solves. It has to do with having a big glowy icon right there that can be clicked on to open it.
Is it less efficient? Of course it is. Nobody ever said human beings were efficient. Good UI isn't something that pretends humans can be or want to be something they're not. Good UI understands humans and works with them, not against them. Good UI understands that humans are stupid creatures that will stop dead in a parking lot waiting for another car to pull out of a spot when there's another spot 20 yards away, because humans would rather waste 80 seconds waiting for a spot to save 15 seconds of walking.
Humans don't care about efficiency. They care about being lazy. Lots of time spent doing something easy is more desirable to people then less time doing something hard. And clicking is way easier than typing, for most people.
When you have no other sane way to get to the data -- like search the web -- you put up with typing. When you've got a few dozen apps sitting right there on your hard drive and your stupid-ass desktop shell makes you type out what you want instead of navigating a menu or two and clicking a button... well, that desktop is a pain in the ass.
That keeps seeming so odd to most Linux developers, being the shell gurus and CLI masters we are. We don't even program with IntelliSense, that's how anti-lazy-typists we are. We aren't like normal computer users. Don't think like them. Don't use computers the same ways they do. So yeah, you get an uber-nerd Linux coder to think up UIs, you end up with some surprising and highly unlikeable/unusable results. Like gnome-shell. And, to a lesser extent, Unity.