How do they not help each other out? That's how trades work. Need for Need. He probably could get more for Varly, but he doesn't have a ton of value anymore either. He is also injury prone, he's 34 yrs old making 5M and just had a season where his sv% dipped to .911. Varly hasn't played more than 50 games in 4 yrs.
Mrazek very well could continue his poor play or continue to have injury issues especially now that he is 30 but this year based on his career numbers does look like a one off and as I stated earlier, he can serve a purpose like bring teams to the cap floor. For example, if the Yotes need to get to the floor, they take Mrazeks cap hit, we save money to pursue say a Gibson, since we are a team looking for a deep playoff run and possibly have a cheap backup like Woll. I still don't necessarily see that as a winning combo but the parody around the league when it comes to goalies as well as the cap isn't in our favor. Unless we can draft and develop a Hellebuyck kind of goalie, we are going to have question marks for a while.