To be honest, I do not know if this was just part of the upgrade, or add-ons by admin (site owner).
However, if you have not read it, please be aware that unlike using the emoji in a post, or PM, when using it as your Reaction, it will take away 1 point from the posters' Reaction score.
Though, some members are still in that old habit of clicking the Insert Thumbnail / full size button vs attaching the media, then clicking the Post reply button.