using anything digital that can lose data because of any kind of hardware or software malfunctions is not the "most secure and safe wallet" ever. and when you are talking about something that you carry around with you and can simply be lost or even stolen (your cell phone) then you are decreasing your security intentionally!

the most secure wallet is what you create offline and will always keep offline. if it is hard copy instead of anything digital then you get a bonus point to your security. example: paper wallet.
if you encrypt it then, you get another extra point for security.