Sometimes we share files with others as proposals. Like a lessor to a lessee for a lease proposal. It can be a new business proposal etc. It may include sensitive data for a meeting which may change in the future. During covid times we are all negotiating. So if an option exists which shares passwords for just one time viewing we can send files which the other party may not be able to use after the call it will help. It will help the user to share file just once & then it expires. It means not being able to share after that call. Yes they can take screen shots but atleast they cant send files for subsequent circulation & sharing