I mean, there is some legitimate concerns. For example, in theory, someone could register a domain "αpple.com" and use that to send phishing mails. That "α" is an alpha. The more alphabets and letter variants you allow, the more lookalikes there will be.

But yeah, in practice, domain registrars check that you're not registering such a lookalike domain and then that's not really a problem, as far as I'm aware.