[stickfigure]

Zelle (possibly just "as implemented by the banks I've interacted with") has very small limits - a couple thousand dollars.

[TazeTSchnitzel]

Are people really going to make big transactions using Facebook money?

[stickfigure]

People will make whatever size transactions they need to make by whatever mechanism they trust.

If Zelle cannot make the transaction happen, it is out of the running. Full stop.