The "reason" is very simple. The kept version is the higher quality of the two.
Yes very simple reason. Until you dont put a stop to practice to consent useless upload at 1080x 1920 or more , instead of the good 720x1280 (very easy to download for everyone), they will be there ever someone that also one week later can stole your video and this generate a useless "war for who upload with higher quality" and so many merged will be produced.
If that wasn't possible introducing a new rule, a user that understand that is impossibile stole a video already on site, would avoid to uploading it and naturally a great number of merged would disappear.
Why would we artificially limit image sizes when the social media platforms offer higher resolution versions (assuming the platform didn’t upscale the image)?
Also, no one on this site owns the uploaded image, unless they are the copyright holder. There is a good chance that if you aren’t the photographer or model, then there is no copyright or ownership here.
More pixel dont means better video and overall, all these merged would disappear, because if you try to upload a video already on site this would be deleted.
Agreeing with Chainer. If the original is filmed at a higher pixel resolution, then that larger version will work out to mean a “better” video. On the other hand if the larger video is upscaled then it will unlikely be better.
Then you have different levels of compression and the types of CODECs. It gets messy, but dimensions are not a pure signifier of quality differences, which is a reason mods will get tired of needing to compare merges.
Can't wait to hear the "reason" of why this was taken away from me when I had this up first and did it by the book.