Unicode characters in URLs can be SEO-friendly if they are properly encoded, but there are some potential drawbacks.
Some search engines may not handle Unicode characters in URLs properly, which can result in crawl errors or lower indexing of your pages. Additionally, some web browsers may not display Unicode characters correctly in the address bar, which can create a poor user experience.
To ensure Unicode characters in URLs are SEO-friendly, it is best to encode them using percent-encoding, which converts them into a format that is recognized by all browsers and search engines.
In conclusion, it is possible for Unicode URLs to be SEO-friendly, but it's important to take the proper steps to ensure that they are properly encoded and display correctly for users and search engines.