It turns out that emoticons are considered a symbol, so they can beef up your passwords and make them more secure in combination with letters and numbers. Here’s how.
Edit: Oh. Did a "Wooosh" happen to me right now? Are you being ironic and referring to the XKCD thing about how to make a secure password using words in phrases?
Well they have to be the same on different devices, like you log in to Lemmy on your PC and then on your phone. Also sometimes it seems the icons change, or there are new ones and maybe old ones are removed ...
Emojis are standardized. They may look different in different devices, but the code of a "raised hands" emoji will always be the same, just like the code for A is always the same.
That's a good question, and yeah, I guess you'd either avoid using emojis or accept the fact that they're not universally supported.
Having said that, some people use non-ascii characters in their passwords, such as Œ which is a valid letter in some alphabets, and they'd run onto the same issue.