Why can you not just sign in with email address on phone?

I am using my student email and I can't log in without having it connected to my other emails, google or Apple ID what is completly pointless. Now I can't log in on my phone because my email address already has an account connected.... The whole point of the creative cloud would be to make you life more simple? How is this simple? I have to take 20 more steps just to transfer my files to the creative cloud from my phone. There should be an option to sign in with email why is that so difficult?