The thing about Discord is that it's condensed thoughts that have little to no substance and the conversation shifts too quickly. You can manage this slightly by having different channels for different topics, but it still doesn't do the job as well as forums can.
With a forum, you can have an in-depth conversation about a specific pet site with the likes/dislikes, etc., and go further into detail.
Nobody (the majority) wants to read a paragraph or two about a pet site in one chat message... they might skim it, but they won't fully be able to comprehend it before the chat pushes it deeper and deeper to the point of that it's not seen by all members or forgotten in 15 minutes. On the other hand, people who come to forums expect to read something in-depth and want to have a deeper conversation on the topic, even if they only have a one-liner reply to add to the message.
Both have their places, but I think both places are good for all audiences: Chat for quick conversations and forums for detailed conversations that can be referenced at any time.
The ultimate would be a chatbox on the forum and the messages recorded as a new reply in a thread every 20 posts, both for SEO and for looking back on topics to bring back up in the future as new topics to discuss.
