Antivirus for mobile devices? Yes, in my opinion, a waste of RAM, ROM and battery life.
To start with, what's Android malware?
A virus is a type of malicious software (malware) program, the likes of which have been infecting your PCs for decades. As the Android platform has developed and became more widely used, so too has the number of potential threats to the system. Viruses don't actually infect Android, because they don't self-replicate, but the term gets used nonetheless.
Security reports – usually from antivirus and security companies – regularly tell us that the threats are on the rise. Whether you believe these reports or, think they're simply trying to scare you into installing an app, it's a good idea to know as much as you can about Android viruses and where they come from.
Where can you get Android malware from?
The biggest malware data base from Android is indeed the Play Store, offering thousands of apps. But there are plenty of other delivery mechanisms for viruses and malware. Emails with attachments – much like the ones you get on your PC – or MMSs that get automatically downloaded, hacks on popular apps such as WhatsApp, phishing scams, fake apps, APKs you've installed manually (outside of the Play Store) or clicking suspect download links, among others.
Why you don't need one?
-Permission Manager: you have listed every permission every app uses and have the option to disable a specific permission on an app. For example, there's no need why AirBrush Photo Editor would need your location, you can disable that permission from the app settings.
-Wipe, track and block phone: it's already included on Google's security options, no need to install Avast for that.
-You can create extra system accounts with less privileges to maximize security on daily basis.
-Device Administrator: built-in tool to enable and disable who can administer your device.
-Unknown sources: by default, and just in case you downloaded an infected Play Store app, no apps will be able to download from anything but the original Play Store-
-Credential storage: manage, install, or clear certificates on your device.
-Trust agents: set features like Trusted Places or Trusted Voice.
-Usage access: manage what apps have access to app-usage data on your device.
-App veryfing: Google will run a verification every time in a while to check apps and their permissions.
The bottom line is there's absolutely nothing wrong with these companies offering alternatives to existing services, especially if it gets people actively thinking about keeping themselves secure. It's just that in terms of malware protection you're probably already protected by Google — or just by common sense. Don't click on suspect links in unsolicited emails or text messages. Don't install an app that mysteriously downloaded itself to your phone or tablet. Only use reputable app stores like Google Play or the Amazon Appstore.
The reputable antivirus software companies out there are fully aware that there's no need for an active scanning tool on most phones and tablets, and that's why you see so many other features in these apps now.