Yeah this doesn't sound too great of an idea. Would you have to type your bitcoin address in each time too? Not exactly easy to remember.
Please learn before speaking:
https://www.youtube.com/watch?v=3eepEWTnRTcMan I wish Google would add a hardware wallet into Nexus 5 (or some other smartphone company). Can you imagine if every smartphone could be also used as a hardware secured authentication device/Bitcoin wallet?