I wouldn't under estimate the amount of friction reduced in having an app on your phone which a) is always with you, b) can also record top quality video and c) has a data plan good enough to upload there and then.
Yup, definitely. Effective mobile editing was a big driver of it's success.
That being said, while it's definitely more effective and popular on mobile how much of that is just down to more people using the internet on mobile relative to desktop.
This is unlike Maps or Uber which only make sense with mobile and always available location.
I wish I could do software development from my phone the way people casually watch tiktok videos. The least unproductive thing I can currently do when trapped with only a phone is read HN.