When using Boxcryptor you can use a login page from the cloud provider, but when using WebDAV on the Cryptomator iOS app, you need to enter the credentials (password) directly into the app. It feels less safe.
see notes here: https://docs.cryptomator.org/en/latest/ios/vault-management/
WebDAV is just a protocol. Its on the service provider to either provide an authentication process (like dropbox, google, etc) mainly via an API, or just a WebDAV connection.
There are cases where you just need the protocol to connect (example: with WebDAV I can connect to my private server without having an authentication layer programmed first)
In these cases you have to store the credentials local. In case of iOS ist the iOS keychain.
Thank you. It helped me.
Well, when using Boxcryptor I could directly connect to my Strato HiDrive account. It is a little disappointing to see that Cryptomator supports only four big cloud providers and otherwise defaults to WebDAV.
Of course, Boxcryptor has a payed subscription model and can do more of these little things. But at a cost of 9,99 EUR in the iOS AppStore I expected a little more from the Cryptomator app than just the basics.