Emoji domains seems to be next big internet trend, but I think they are a real nightmare, see below. But let me shortly explain, how Emoji domains are working technical. If you type in ✌, or any other "non basic" unicode char, into the address bar of your browser, it converts the unicode into Punycode: ✌.example becomes xn--7bi.example and that's it!
First of all, I SIMPLY CAN'T TYPE IN EMOTICONS ON THE MOST DEVICES! In the best case, I can type in the emoticons on my mobile phone. In the worst case not even there. My LG G4 for example doesn't support the newest Unicode chars (-> new emojis). If someone sends me some new emojis, I only see U+25A1, the magic white Box □, which is often used to represent a missing ideograph. Every time you want to type an emoticon you have to use a special "Emoji-keyboard", which doesn't exist on many devices and no, I don't want to install one. I prefer to be able to type in domain names directly with my normal keyboard. Additionatly, there are many computer programmes, which doesn't support Emoji Domains.
There is also a security risk: If all you can use all unicode characters in domain names, you can do hijacking. Assume you want to imitate apple.com. You don't want that your victim sees, that he's on a fake site. You can use unicode chars and create the domain applе.com, you are maybe not even able to see it, but it will lead the victim to "xn--appl-y4d.com", where you have placed your phising site. We used the cyrillic letter Ye, U+0435. Chrome and Firefox are trying to prevent this form of attack by showing the punycode in the address bar. Nevertheless, allowing all unicode chars in domains is dangerous.
PS: It seems like nano doesn't support emojis very well ...: