It sends if a MMS, with 2 or more recipients. If just sending to one recipient, it says to go to Settings and change input mode to automatic. Specifically, a pop-up says:
"Change input mode
In your current input mode, special characters, such as emojis and letters with diacritics, may not be shown correctly on the recipient device.
To resolve this, tap SETTINGS below, then set the input mode to Automatic, or tap SEND to send the message anyway."
When I do tap on Settings, the only option to click on is "Manage SIM card messages." There is no option to change the input mode. If I tap Send and send anyway, the emojis show up as question marks ??? This is using Samsung messages app.