[tshaddox]

It's just as straightforward to interpret the browser bar as only being a search bar that accepts any textual representation of intent from the user and does its best to interpret that intent (that's what search engines do, after all). And if that intent looks like a URL [0], then it might interpret that as your intent and load that URL. It's just one of many cases that are expected from a search engine–other might include showing a map for a query that looks like a location, doing arithmetic calculations for queries that look like arithmetic expressions, etc.

[0] Or a domain...even the most tech-savvy among us probably types in domains without examining the difference between a domain and a URL or how software might detect whether a given string looks like a domain