In this vintage video segment from Curiosity Show, we learn about self-starting siphons. These things start a flow of water without the user having to squeeze a pump or suck on a tube, which is a distinct benefit.
In the segment, we also observe the limitations of self-starting siphons. Because the act of submersion starts the flow, we're limited to siphoning water out of very full vessels. But still, this could be useful for a home aquarium, which is one of a thousand scenarios in which you don't want to use a mouth-primed siphon.
The best part of the segment is when presenter Rob Morrison shows how to make your own self-starting siphon. File this under "Handy stuff you can do with bendy straws." Tune in and enjoy this simple physics demo: