The $50B is for the 100M users MAUs, 50M of which are active daily[1]. They have a billion downloads as well.
As a comparison, Facebook paid $1B for 30-40M signups on Instagram2[2][3]. Their MAUs and DAUs at the time would've been a small fraction of that.
So if we consider TikTok's downloads to be equivalent to Instagram's signups, the valuation isn't crazy at all (especially since TikTok has revenue).
1. https://www.cnbc.com/2020/08/24/tiktok-reveals-us-global-use...
2. https://www.vox.com/2017/4/9/15235940/facebook-instagram-acq...
3. https://techcrunch.com/2012/04/13/instagrams-user-count-now-...
> ByteDance has had a party committee since 2017 and is headed by CCP secretary and company editor-in-chief Zhang Fuping (張輔評), reported Human Rights Watch. Members of the committee hold regular gatherings at which they study speeches by Chinese Chairman Xi Jinping (習近平) and "pledge to follow the party in technological innovation."
> In addition, ByteDance on April 25, 2019, signed a strategic cooperation agreement with the Ministry of Public Security's Press and Publicity Bureau (公安部新聞宣傳局) in Beijing. The agreement was billed as "aiming to give full play to the professional technology and platform advantages of Toutiao and Tiktok in big data analysis," strengthen the creation and production of "public security new media works," boost "network influence and online discourse power," and enhance "public security propaganda, guidance, influence, and credibility," among other aspects.
https://www.asiatimesfinancial.com/ccp-announces-plan-to-tak...