Still learning this game and don’t really understand the purpose of Cassian and Iden’s ability to deploy with the Operative Rank.

I understand that for list building purposes, both are commanders and take a Commanders slot.

Whats the point of deploying as an Operative other than to get Infiltrate?

Is this just a way to get a third Operative on the table at once or to give more list building options?

What other advantage is there to deploy as an Operative?

You nailed it. You're really only becoming an operative to get infiltrate. That's it. Operatives are just worse Commanders.

24 minutes ago, thepopemobile100 said:

You nailed it. You're really only becoming an operative to get infiltrate. That's it. Operatives are just worse Commanders.

Worse in that you can't use their courage on units within range 3 to prevent panic, in case the OP wasn't aware. They also can't be nominated (chosen to be the one who is issuing orders) during the command phase if you play a generic command card (Push, Assault, etc.).