It has been widely known and makes sense that Facebook wants to keep users on their website rather than sending them away. To do this, Facebook tends to suggest more posts that are not linked to a third party source compared to posts that are linked to a third party source. It is under this methodology that helps them keep more users active on their website.
Over the past few months, information has come out that Facebook has now begun to favor native video uploads versus third party uploads such as YouTube. Watching a YouTube video does not instantly take users away from Facebook but it may certainly market and support their website as a mean to entertain internet users. With Facebook and Google certainly not getting along and Facebook announcing they were limiting the reach of third party images, this is a worthy theory to test. Search Engine Journal has tested this theory themselves to see if it is in fact true.
In their study, they integrated as many variables as possible to be sure they would get the most accurate numbers as possible. They identified 3 facebook pages, all with an honest following, and found 7 videos that were ideal for each page. This totaled 21 videos and 42 total facebook video updates. One video type was set to be uploaded on a specific day of the week and a specific time. The other video type would then be uploaded the week after at the exact same time. In case posting a week later impacts the engagement of a post, they posted half of the native videos first and half of youtube video embeds first.
The study came back with numbers indicating that Facebook does in fact give precedence to native videos. Native videos saw a reach of 2x more people. With a higher reach, these posts see around 2x more likes, 3x more shares, and 7x more comments.
Based off this Search Engine Journals study and other speculation it absolutely seems that Facebook favors native videos over third party video, at least versus YouTube.