SEO impact of using non-Latin characters in URL
Some SEOs are wary of using these non-Latin characters in URLs because of the way it might display in certain browsers, or in certain text cases when the link is copied and pasted somewhere online. While having spammy-looking links is never a good thing, I personally think the possible benefit in search results is worth the drawback.
For example, the Japanese Wikipedia page for soccer (サッカー) might display as
<http://ja.wikipedia.org/wiki/サッカー>, depending on the browser you use.
While some SEOs will be afraid of the potential for your URLs to look spammy with strings of numbers letters and percent signs, the benefit of having the non-Latin characters show up bolded in the URL of your search snippet is worth that, especially when most browsers are displaying the original characters anyway.