It is a nice idea, but not useful. Youtube will demonetize your videos immediately as they did with all the vine compilation and you will most probably get Copyright stricked.
Most grow them and promote products or either sell them to another company/indivisual where they then completely transform it. From what I can tell, they just scrape or download these videos manually and then edit them.
the problem with using TT videos is that they watermark them with a moving watermark and I am fairly sure it is against TOS to upload someone elses TT video on your TT account.
If we can get JV to upload TT videos eventually, you would have a much better time scraping IG, FB, Twitter, etc and uploading that content to TT