It's just a matter of preference..
One reason why I'm using OCC is to have only pure gasoline ignited in the combustion chamber. I don't want it contaminated with oil which can lower the octane value that can lead to engine pinging.
In the local Philippine forum, I often read complaints on 93 RON gasoline and engine pinging. Forumers are often advised to use preferably higher than 95 RON.
I have yet to hear the actual engine pinging they are telling..