But how do we know they're swapping and not using a third-party provider like Changelly? Is there no way to easily verify it?
Not sure how to verify it. But probably if we did some transaction we can see from the explorer if the funds have been directed to/on another exchange.
This is technically not a Bitcoin wallet, but more like an exchange for swapping Bitcoins for ethereum and other altcoins.
There are some wallets that able to add exchange feature. Since we can retrieved back up phrase for this, somehow I believe its partly called a wallet but you are right the function works like an exchangw but technical term appropriate is dApp.
Any idea if we can use some hardware wallet here like Trezor hardware wallet? Like if we want to make transaction to our harware wallet with this crosschain atomic swap?
If you connect metamask like most dApps, you can used to exchange it but interesting question since we are gonna used a hardwallet for transaction. As of now, only ledger is the only hardwallet I can see supported.
Will try soon to get more clarity on this.