I like this trade, there are a lot of positives to it.
We get a high leverage reliever, who can slot right into a setup slot and has plenty of control left. So far this offseason good relievers have been getting paid big time. Swanson has a super sexy statcast page. https://baseballsavant.mlb.com/savant-player/erik-swanson-657024?stats=statcast-r-pitching-mlb
Macko is the Mariners 8th ranked prospect on fangraphs, he'll probably slot in top 10 for us as well. He's way more than your low level lottery ticket.
Teoscar will be getting about 15 million next year, if they go out and sign a CFer and put that money towards the signing it'll be fine. This allows Springer to move into RF.