If you are careful, you do not need any antivirus on an android device.
The only thing that some antiviruses can do is if you have root access (by default you do not) you can reset your device should it get stolen. You can even take pictures and videos, some you can even listen to the background as well as track via the GPS.
By the way, I do use mine this way
Helped out once! I took a picture and got a clean image of the dudes face as well as gave the police the GPS location and had my phone back the same day.
The only thing that some antiviruses can do is if you have root access (by default you do not) you can reset your device should it get stolen. You can even take pictures and videos, some you can even listen to the background as well as track via the GPS.
By the way, I do use mine this way