A-Series Chips In The Rumored "Low Cost" Macbooks...

Can someone explain the benefits of using an A-series chip in the rumored new "low-cost" MacBooks vs. using an older M-Series chip?

Also, is there anything interesting in the idea of MacOS running on an A-Series chip. Like, could this foretell a flip phone that runs iPhoneOS when closed and MacOS when open. Just spitballing here...