Does Anti-Virus software help reduce malicious attks. on devices with older Android O/S's?

[AC Question]

I'm curious to know if having anti-virus software on legacy o/s tablets and phones help reduce the chance of malicious software attacking our devices?

Considering the sheer number of people with older Android O/S devices, surely it's reasonably safe, if you use 3rd party anti-virus software?

I'd rather not be fear mongered into upgrading a device - if not necessary.

 

[ManiacJoe]

Of course, AV software helps protect your device, as long as it is from a well known company.
How much it helps protect your device is open for debate.