Pest control, as long as they are not poisonous. In some places and countries yellow pitons and white Boa are deliberately kept in and around rural houses as pest control. Nothing like that around here but last few years there's couple of green garter snakes, this year they are about 1.5 meters long and during the day hide in rose garden bushes and in hedges. Some times I see them with a bump which means they ate a mouse or a rat but are not big enough to be dangerous to dogs and cats. Gone in hibernation now but can't find where, not in the house.
