If you need a circuit that converts a momentary push button to a latching switch with low standby current, this design might suit your needs.

Turn power on and off with a minimal switch or even no switch at all by adding a flip-flop to a SPST for a classic push-on, push-off Continue Reading ...

In this case, [Tod] wanted to use a momentary tactile switch to turn something on and ... What he really needed in this case is a flip-flop but lacking a chip for that he went with the 555 because ...