Public chain is about crypto currency. Why blockchain is invented, because we need decentralised money. Why etheruem be invented, because we need a more usable decentralised money.
If we could not create a popular money, then AE need not to exist.
There are too many currency coins. Look at BCH, BTC, XRP, XMR, LTC, USDT, DASH, ZCASH, BTG, DOGE, BCN, BCD, etc, etc. Aeternity is NOT another stupid currency coin, there are already too many of those, more than 3000+, and most of them are WORTHLESS.
Yes, most of the currencies are useless. We only need few of them.
Bitcoin——digital gold, strong community
Etheruem——the first currency with turning complete smart contract , this make ETH can be accepted in many use cases related with money, like ICO, Betting, collection,pay.
So AE add smart contract, Oracle, state channel, to make sure AE currency can be used in more use cases. These use cases other program can not handle well.
Public blockchain is all about money. The tech is to create unique use cases for the currency to be accepted.