Uh, ok, like another reply says, how often do you need to look at every application on your system?
Here are a few scenarios that come to mind.
1) Need to run a specific application.
a) Click the Dash, type a few letters, click the application or,
b) Click the Dash, click the categories view, filter by category, click the application or,
c) Find your application, drag it to the Launcher for quick access
2) Need to see all "Internet" applications.
a) Click the Dash, click the categories view, filter by category
3) Need to launch an application, but don't remember it's name, only something vague about it.
a) Click the Dash, type a few letters (not necessarily the beginning of the name), go aha!, click the application
4) Need to find a document that you were working on, but don't quite remember the name or where you put it.
a) Click the Dash, type a few letters (not necessarily the beginning of the name), go aha!, click the document
On the classic interface, 1b and 2a are possible. The rest are not. So while Unity may require a couple more keypresses in some comparisons, it seems more capable and flexible to me as a desktop.
Now ads are annoying, yes. I don't like that. Thankfully you can disable it. I also don't like the global menu, which this article is about. They seem to be changing it.