What happens if I disable emoji?
WordPress by default inject a JavaScript code to convert emojis in the text to images.
For example, a text emoji like :) or unicode 😃 will be converted to an image .
The advantage of this approach is that emojis will be standardized and visible to all browsers if Unicode emojis are not supported. However, the disadvantage is, it adds a JavaScript file that downloads an image for each and every emoji.
We recommend to disable WordPress' inbuilt emoji and use unicode emojis. Like: 😊 🎉 ✈️ (Google "smile emoji unicode").