Err, localizing the site is already offering something better. I'd say go for it. Are you suggesting non-english people simply shouldn't have access to such a site because it already exists in english and the company chose not to build a localized version? There's a huge market there ripe for the picking and many American companies aren't taking notice.
I'm not saying he shouldn't do it, but if I'm at a gathering and person A says "I built this new web-app that does cool new thing X" and person B says "I copied site B, only I changed the text to Spanish", it's pretty clear who I'm going to want to chat with.