Through my android using life I have gone back and forth. I've pretty much tried them all and I see no purpose. Just don't download random sketchy apps and you'll be fine. I've never had problems.
Just read an article about a hacking competition in China. A Google Google Pixel was hacked in 60 Seconds. I'm sure Google will be addressing it you'll see it. I believe that for anyone to think you're completely safe on any phone is really naïve
Apparently hacks tend to hack root access, and so anti virus software on an unrooted device without root access is powerless. I don't really know though.