Because search is the new navigation, whether you like it or not.
Yep, it's the new navigation because of search noted above and because of typo squatters with malware.
Not on mobile. Not to launch an app.
I never type in URLs directly. It is either a single click on the menu bar/blank tab, or else I go via a search engine to reduce the risk of landing on a typo squatter.
I've seen several ads on TV and billboards which just say "Search for $brandname $productname" instead of a URL.