Excellent use of the phrase "trade offs". Because effectively all you are doing is trading resources in a similar way to how a financial portfolio maybe managed. You're buying disk space and selling CPU (and probably a bit of RAM too to hold the compress and uncompress versions).

It's great to have the ability to do this resource trading but it's important to realize that nothing comes free. The only way to justify the resource trade is to determine and measure the benefits against you're business requirements. It may seem like great news to have released so much disk space, but disk is relatively cheap compared to other hardware resources.

If performance is your goal then compression on very large tables can help considerably. If you dig deep into MPP appliances like Netezza you will find that part of the way they achieve staggering performance is by using compression algorithms close to disk.