Moved this to Contribute > UX as I agree we should update our copy.
You can already do so yourself: any admin can customize the badge description via Admin → Badges → First Reaction → Edit and update the long description to something like:
“This badge is granted the first time you use the emoji reactions picker (hover over the
button and select an emoji like
,
, etc.) to react to a post. This is different from a standard Like — it lets you express a more specific emotion!”