Why Microsoft want to buy TikTok Once Upon a Time

Lots of people guessing why a productive tool company want to buy a such a toy, childish and nonsensical App. Microsoft want to use TikTok as a channel to sell Microsoft 365? Want to create a TikTok for Business and profit more? Want to expand its market to Social Media and counter the competition from Facebook and Google? Want to save TikTok from the ban?

But I feel all the above list may only partly true, here must be some other reasons.

The smile of Mona Lisa