Exactly lmao. People mistakingly believe that the only thing you need to join the crew is for Luffy to want you. And whilst that's true on paper since Luffy's the captain, the reality is that the straw hats are a group of extremely close friends. A family. There's a reason Oda takes care to have not only Luffy, but the rest of the crew be friends with the future nakama too. They need to feel like and get on with the rest of the family once they join. Not just with Luffy.
Even with Robin who was purposefully supposed to be distant and a mystery to the crew, Oda still had her meet everyone in her intro so they at least knew who she was. You can go through each member and see how they were already familiar and interacted with the crew well before joining:
And these are just the casual interactions. All of them also have more personal and meaningful interactions with some members too. But that's just how Oda does things. They'll feel like a crew member before they even join. Slotting in right alongside them and their dynamics. Having an ongoing relationship with the crew right up until the end of the arc where they make it official.
A little something like what we're seeing with a certain bunny character...
Yamao being a complete and utter stranger to the straw hats a whopping 50 chapters after her intro is extremely strange. But when you consider that all the interactions she should've been having with the crew are instead happening with Momo and Shinobu, everything starts to make sense regarding her character's future.