Shouldn't the browsers change those extra Unicode symbols to ASCII ones? For example, like with russian domains they change to xn---yatta-yatta-yatta and you can see that?
The browser has to convert internationalised domain names to ASCII (using the ACE prefix 'xn--' and Punycode), as Domain Name System labels can only contain ASCII (or, actually, a subset thereof). But the problem is that not all browsers make it very conspicuous to the user that an IDN has been encountered. Hence it's entirely possible for a user to click on a link without realising that the link uses an IDN rather than a traditional ASCII domain name. And phishers exploit this.