You may be right.
A common technique in the deadlift is to pull the shoulders back and down with the lats to keep the upper back tight. So perhaps not their "function".
Yes. This is what doesn't make any sense when lifters say that lots of rows and big lats are good for balancing out pressing volume. Both just lead to internal rotation. I think strict rear delt work like face pulls are more effective for that purpose.
When you bench pl style there is a lot of lat involvement.