On a business page is it better to post a video direct to facebook or upload to youtube and post the link?
For a more streamlined experience for the viewer, posting directly to Facebook means that it will "autoplay" if people scroll past it (provided they haven't turned this off in their data settings), and it makes sharing easier. I prefer uploading to Facebook.
Sometimes if there's music in the video it will mute the video after a few minutes of it being uploaded due to copyright. There is a work-around for this though. Click "restore audio". If the video includes dancing, then it falls under the fair use policy under "the music isn't the main focus of the video" (that's not the exact wording, I forget what it says exactly but it's something like that). I've done it over hundred times and it's never been a problem.
When would YouTube be preferable over Facebook?
If the video is aimed towards kids ages 5 to 12, then YouTube is the most popular platform. Sometimes it's worth uploading the same video to YouTube as well, just for this reason. Sharing the FB one on FB - but using keywords on YouTube to help kids find that version.
For reaching teens, Instagram would be the preferred platform. (Or Tiktok, if the government doesn't end up banning it).