Four months is barely enough time to get a good grounding of what work is like at that company, and the company itself looses out on training someone and then having them leave after a short period of time. For large companies, that works fine because it's an investment into whether you would be a good full-time hire. But it's not universally helpful.
I've found that 8 month co-ops are the most ideal. Less running around, you spend a good stable 6 months doing work (depending on the company) as a full-time employee would, and the company benefits from it as well.
Co-ops in general though teach you how to pack light and not carry unnecessary baggage. I've always grown up on the move so it was easy for me to adapt, but it helpful for those who don't do it often.