Short papers at computer science conferences What is the purpose of short papers at computer science conferences?

I’m a first year PhD student. I spent a few months working with my supervisor on a long paper that we submitted to a conference. I then spent two weeks working on a short paper for the same conference. My supervisor said that it is fine to submit.

Would it have been better working on four or five short papers instead of one long paper? Or are short papers not well regarded at all—should I not consider working on them in the future?
The value of short papers at CS conferences (I guess this holds true for other subjects, as well) is that they provide you a way to discuss early results of a study in a venue of people who have similar interests.

You receive feedback before the "real thing". Some conferences in CS do also publish short papers in their proceedings but many of them do not. Under the publish or perish viewpoint regular papers carry more value. 

On the other hand, a short paper is ideally followed by a regular paper, after some time. After all, you would make use of all the feedback received to produce the regular paper at another venue.

You ask "Would it of been better working on 4-5 short papers instead of 1 long paper?" 

It depends on what you need to achieve. Five publications are likely better than one publication. But short papers often are not published. Even if they were: how much time would it take to have 5 papers peer-reviewed and accepted at X conferences, instead of a single 1 in a single conference? With a regular paper only, you have more time to move to the next thing!