I chose peer to peer currecy and of course smart contracts.
I have seen the development of the two coins above, such as Bitcoin, Litecoin, Dogecoin, Ethereum and Binance which looks good for long-term investments, although Dogecoin is like a cute coin, many choose it for investment.
Stable money seems good for storing profits from trading, the more choice of altcoin types it will be easier for us to choose.