In west coast cities, stop signs seem to serve the purpose of letting pedestrians exert their legal right of way where it would otherwise be taken by cars. Without stop signs, cars are not really likely to stop and pedestrians will wait until the road is simply clear rather than playing a one sided mortal game of chicken. The result is that cars can pretend that the pedestrian doesn't actually want to cross. With a stop sign, pedestrians can reason that a car has to stop for the stop sign, and so they will also be able to walk.
That said I think stop signs is a terrible solution to this issue.
That said I think stop signs is a terrible solution to this issue.