Your wallet is as safe as in a normal phone, meaning is as safe as your phone is from malware. Keep only a small amount in your phone wallet and use it as a hot wallet, larger quantities should be kept in more secure wallets.
For an iPhone maybe... but on Android, having a rooted phone effectively removes a lot of the safety systems... Usually, apps on Android are only able to run within their own sandbox and have very limited access to the file system and no access to other apps data. However, when rooted, if an app gains "root" permissions it basically gets unlimited access to EVERYTHING on the phone, including data belonging to other apps... like wallet files!
Be VERY careful if you are using bitcoins on a rooted phone.
If you want to be safe much better to don't root your phone.. for much safe of your wallet..
The other thing rooted phone is just only for use modification of your phone and increase the speed and improves battery efficient.
For iphone honestly this is much secured os that i never heard that there are someone hack or make a virus for that phone that i think much more safe to use..