Those Samsung user who's phone doesn't support S Secure app, They can install 'Google Files App'.In this app there is a folder named 'Safe folder'.It is Google's app so you can trust it & also better than any third party app.
Yes I know but there are apps named Google photos & drive which is pre-installed in every android phone.Not only both have permission for ur photos and video but also people keeps their photos on drive for future.So u don't be fool.