I would do Hoffman for Barrie… but why the retention of salary in the deal?

Both players have the exact same deal, length and amount, so retaining the same amount on each side doesn’t make sense.

I’m more confuse as to why a team going through a rebuild would bring in Hoffman instead of trading Barrie for assets

It leaves the potential for a double retained flip of those players without needing a 3rd party broker at a later date.
I'm actually surprised teams don't do this.

yep, that exactly this idea, both players can bring pick at trade dead line because tham cap can be only 25 percent, its good for nashville and montreal at same time

Probably because it doesn't make a ton of sense to use two retention slots on what would basically be a return on one player. If a team really wants a player with double retention they can make it work for a 4th or 5th to a third team easy enough. This is theoretically not getting anything for using one of your retention slots. I wouldn't expect the return for the player to be so good that it would be worth while. Now you can only retain on one more player so for Montreal only having Edmundson as a UFA it might be alright but if there was a potential deal to move another player like Savard or Armia or Anderson with a bit of retention you couldn't. Even just being that third party broker and getting a mid pick isn't possible.

It's situational, as the player with double retention has to be worth more than the player at single retention + a 4th.
If Hoffman is worth a 2nd at $1.125M and it takes you 2 slots to get that, it could be more beneficial than using 1 slot for a 3rd and 1 slot for a 4th.
Quality versus quantity scenario.

I'm not saying it should happen all the time, only that I'm surprised it doesn't happen at all.

Lmao no I don’t want anything to do wit Hoffman. I’d rather have a top 4 offensive defenseman over a player that only is good for scoring goals but only has 9 of them this year. Less than barrie I might add.