Android usually has no confirmation dialogs, it just does the action then shows a tiny 1-2 seconds popup with a button to undo it. This is ok for closing single tabs, since it's easy to restore a single tab from history. But it's not ok for closing all tabs\multiple tabs since android Firefox can't restore "all" tabs, or previous profiles without root (Firefox sync is irrelevant and not a workaround anyway, both because you'd need another device you might not have, not being ergonomic even when it works and the sync being likely to happen before you can save the tabs in another device).
All these problems can be avoided with a gui for a persistent confirmation for the >1 closed tabs or if you don't want that, the godawful close all tabs button in the overview.