I think there is no difference in using the mobile wallets or desktop wallets. Both are same and both have the same type of risk.
1. People can not bypass the finger print if nobody collect your finger print sample from you. (There are many videos on YouTube about hacking finger print. May be some tricks are working) So thus people can access your wallet.
Not everyone can bypass the finger print and i guess it is safe. Even if few experts can hack finger prints, even then your phone is protected by pass code and passwords.
2. If you lost your phone then people need to restore/hard reset your phone for remove the finger print and pin And all apps will be removed from the phone Except the stoke apps. So the wallets also will be removed and fund remain safe.
Losing an iphone, you are 100$ safe. On an android phone, the hard reset will leave no traces for the hacker to hack your bitcoins.
3. If you take any screenshot of your private key and keep it on your phone then if you download any untrusted third-party apps which take the permission of controlling SD card Data/Photos then hacker can hack your wallet with the help of these third party apps.
Never keep the photos of private key in your phone. That's the best way to remain safe.