The file is the collaboration
Live cursors are genuinely impressive — five people drawing at once, presence bubbles, someone's pointer wiggling over the thing they mean. And for a workshop happening right now, in one shared hour, that's the tool. But be honest about the last five times you "collaborated" on a document: was anyone else actually there at the same moment? Or did you work, send, wait, receive, work again?
What the file does better
A .board file emailed to a colleague is collaboration with properties the live board can't offer. It's versioned by default — thinking-v1.board still exists after v3; the live board's Monday state is gone forever unless someone paid for version history. It's deliberate — you send it when the thinking is ready to be seen, not while your half-formed boxes wobble under an audience; anyone who's drawn while five cursors watch knows the performance tax. It's private in transit — it moves over whatever channel you already trust (your email, your chat, your USB stick), touching no third-party whiteboard server. And it's unlockable — no member limit, no expired trial, no acquired-and-sunset startup between you and your own diagram. The file sits in your folder like it's 2004, which turns out to be a feature.
The turn-based rhythm
File collaboration is chess, not ping-pong: I think fully, pass; you think fully, pass back. For actual thinking work — architecture sketches, plans, retros happening across time zones — the turn-based rhythm is not the budget option. Deep-work advocates have argued for years that the asynchronous version is the better one and the live version is the compromise. The exception is the genuine same-hour workshop, and for that: screen-share this board on the call. One person drives, everyone talks. The cursor was never the collaboration — the conversation was.