Basically it is exchanging private keys offchain, you create a pain in the ass for companies like chainalysis because all the histories are mixed and on the other hand the transactions are instantaneous and there is no limit. It's like exchanging money in hand.
Discussion
Ty
This is ridiculously smart if it can be pulled off in a very very secure, trustless manner.
Very clever.
Exchanging private keys to swap funds is a very interesting idea for thwarting chainanalysis. Definitely faster than coinjoining.