Adobe Scan Password Security

The Adobe Scan app has you create a password. However, you can sign in without a password because it gives you the option of signing in through your Google account without a password. So what good is the password you created? Where's the security? 

I delinked Google and Adobe scan, or I thought I did. It explains your email is needed. It's not valid because my email is all that is needed to link them up again and log into Adobe Scan. And my email is right there. When going ahead with this it sends a verification code which is used to link up Google and Adobe Scan.

So where's the security in all this if someone gains access to my device?

Is there an actual way to actually password protect Adobe Scan?

Thx.

Chris