It's a nice addition, but I think it needs some improvements in combination with GIFs. (tested on desktop app with both /spoiiler and || ||)
Uploading a spoilered GIF of your own disabled the fav-button and replaced it with the GIF-indicator. So you can't favorise it anymore. That happened after I closed Discord once and now it's permanent. Also: it didn't autoplay anymore after clicking on it to remove the blur. Since adding one of your own images doesn't create a link on send, post editing isn't even an option if you for example don't want the spoil tag anymore.
You can't add a spoilered GIF in combination with the GIF-button, since selecting one will immediatelly send it. So a prompt, checkbox or anything to mark it as spoiler is missing. Post editing it works, but it destroys the purpose. (You actually have to add a space after the link though, otherwise it'll only mark the link as a spoiler text and the preview is removed. :thinking: Took me a while before realizing.)