The new magic wand button in Gboard is actually Translate for emoji
Emoji has become an integral part of our texting as well as messaging lives. Some people use them rarely while many of them enjoy using them every now and then. If you want to use the emojis in a better way then there is a new feature introduced for Gboard that tries to make the choice for you.
Some of the users have started to see magic wand button on their keyboard. When you have finished writing the sentence, tapping the button will insert many emojis that Gboard thinks are the closest match to what you have written. It has got two modes and tapping once will put an emoji translation after your text and tapping it twice will insert the emoji between each word. Sometimes it works perfectly while in other sentences it is just hit-or-miss thing. At the moment it looks like you are required your keyboard set to English but we may see support for more languages in future. If you need to try it for your device you need to make sure that your Gboard app is updated fully and maybe sign up to the beta program.