I’m not privy to the inner mysteries of Discourse. I was just passing along something I read that might be helpful.
The links should both work if you click on them, yes. The difference—at least as I understand it—is the way Discourse handles the embedding within the post. The way you originally did it, Discourse wasn’t embedding in a way that would allow another Forum user to come along and play the video directly within the post. I grabbed the share URL from the Dropbox page in your older post and tried pasting it into a private conversation I was having with @discobot:
Looks like it works. If I directly paste the Dropbox link, its just as the original was, just a gray blob and why I used Google Keep first to change the 0 to 1.
When I was doing my own testing earlier, I had problems in Firefox when I changed dl=0 to dl=1, and it was sometimes reporting a network error. I think the better solution is to change dl=0 to raw=1, as I indicated above. That provided me with more consistent results in limited testing and appears to be the accepted solution in the Dropbox Community, so if I were you going forward I’d be sure to change the whole thing, not just the final digit.
When pasting a Dropbox video share URL into a Forum post, remember to change the
This yielded this (screenshot, not actual video link). 
roll lol
