[quote=@Gowi]
Or you can post without depending on collabs?[/quote]

The format of writing out full IC posts for one side of a conversation saying something, then the other side taking their turn in a new post, then the first again, is incredibly slow. It will be the Ides of March IRL before it's the Ides of March in the RP. Collabs allow for interactions between characters to begin and end in the same post, written over the course of maybe a few hours if it's especially long. It allows for things to progress much more quickly. It's also much more natural for everyone reading the thread. Instead of having to read and/or scroll through unrelated IC posts occurring on the other half of the continent from the conversation you started reading, you get the beginning, middle and end all continuously. Writing it all at once also allows for the ideas being expressed to have some continuity, and for both sides of the collaboration to comment on and improve each other's side.

Really, it's the superior method in every which way. Every IC interaction between two different players' characters that does not occur in a collab would work better if it occurred in a collab.