I finally understand the "Atomic Swap"

I always wondered how platforms like Shapeshift were able to swap wallet to wallet. It seems that decentralized exchanges would be preferable for decentralized currency. We should be there soon!
If this can displace trading platforms (looking at you Poloniex) crypto should move forward, in my opinion.
Here is a link to the article that made it click for me: https://www.cryptocompare.com/coins/guides/what-are-atomic-swaps/