I have an iPhone 6 and after the last update I can open it with either method (I just don't need to do both at the same time). It's not that bad using the thumbprint - sometimes it's handy.
I have an iPhone 6plus I never used the thumbprint. And I made the Apple Genius guy turn off the password, but he showed me how to turn it on if I needed to do that. I do really like my phone. It's even pink! :)
The thumbprint for some reason scares me oceander, I don't know why.