'Do stuff' happens only once, instead on running every tick while Variable = 1. When Variable changes to anything else but 1, nothing happens, and when Variable becomes 1 again 'Do stuff' is again executed once.
What are you trying to do then? I guess I misunderstood your question as I was just trying to describe how 'trigger once while true' trigger works. You can use 'trigger once while true' with any conditions that would otherwise run each tick or loop, they don't have to be variables :)