While it will be attactive to run him in the command zone, he will also be right at home in countless aristocrats and tokens builds, especially those with Commanders and gameplans that involve sacrificing many creatures per turn
While you have little tutoring to piece together the combo it doesn't matter much as all the cards conveniently support affinity as well as the combo
I am more interested in the ability for it to fix than I am about the 5/5
Then, if you have six or more humans, you're also drawing a card for your troubles
Hakbal, the Surging Soul himself, does a lot in this regard, allowing each merfolk to explore at the start of your combat
Unlike a majority of Secret Lairs nowadays, all three of these Lairs offered strong reprint value