It's easy for you to write "figurehead" but then you don't explain correctly. He is used as a figurehead because he is the nominal leader after Luffy> That's a vice-captain role = Check.
Also, Oda used Zoro as a "figurehead" in Nami's speech about "fighting" and why they should bring him if they want to fight is another way of telling the OP readers that Zoro is the head of the group of fighters after Luffy. Despite that Sanji, Chopper, Luffy, and Brook were in WC but Nami insisted on bringing Zoro, the figurehead, then the others> that means he is the fighter of the crew, Luffy's muscle, and an essential crew member for winning the fight= check.
Oda always portrayed Zoro as the strongest member. The guy who trains all the time and wants to be stronger. He is the combatant of the crew.
You Sanji fans are just haters but Oda shits on you every time by hyping up Zoro.