Yes, for most folks using an english version OS / web browser, typing in a domain may be sufficient security...
However, in the world of IDNs, things do not work as one would always expect ...
For some folks using *non-english* software, typing in a domain is NO guarantee ... IDNs are not exact and thus there is much latitude in how software maps them to domains.
In a nutshell, there is no guarantee that folks typing a domain name in a non-english based OS / web browser - some will get the website they expect, some won't ... such "best guess" behavior is totally contrary to structure of the DNS system; ICANN was warned repeatedly about these threats and yet has allowed IDNs to go ahead anyways ...
Here's an example of something really spooky ...
Click to this thread below and see if you can spot the real amazon.com?
http://www.dnforum.com/showthread.php?t=81129
Ron