Why build the Oerlikon 20mm/70 light AA gun?

[Normanvac]

Hi I have been doing a little research into the Oerlikon 20mm canon and its various uses and it struck me that it was never, as far as I know, put into a tank turret. I would have thought that as a weapon in a recon tank perhaps the Vickers Light it would have been a great asset. Anyone got any info.