Where are the scans uploaded? ...And why?

Hi, I've been using Adobe Scan for a short time. However, I am more than surprised that the scns are not stored on the mobile phone, but are obviously uploaded to an unspecified cloud, from where they then (more than cumbersome) have to be downloaded again.

This procedure is completely incomprehensible to me. Is it possible to turn it off and save all documents only on the device?

If not, what happens to the documents, which may also contain sensitive and personal data? Are they stored at Adobe? Will they be deleted at some point?

I am very grateful for information about this...

Best regards, Lorenz.