Why is a punishment for prison inmates, to pick up trash on highways? Isn't this something we all need to do, not just criminals?

I feel like, that vision of a group of men in bright orange jumpers with the long poles & satchels is making it look like cleaning up our highways/parks/anywhere really, is something of a punishment. Imagine a kid in the car with his parents & they pass by a group of inmates cleaning trash off the road. The kid is going to ask the parents, ‘what are they doing?’ & the parents will reply, ‘those are bad guys who did something wrong. They pick up trash as a punishment for what they did.’ That kid is going to associate criminals & bad behavior with cleaning up the environment, which is in fact, a good behavior.