This is pretty subjective... and not always the best for everyone. Yes, kegging saves time compared to the actual act of bottling. However, how much time do you spend cleaning lines, driving to a store to refill CO2 canisters, and generally messing with the system? I bet the total amount of time spent with a keg system isn't that different than bottling. Now, if bottling is a chore that you hate, and cleaning keg lines is fun... well, lucky you!
As for cost, it sounds like you got lucky and were able to move to kegs VERY cheaply. That's not an option for many people. A good keg system typically runs several hundred dollars.
Also, how easy is it for you to take a 6 pack over to a friend's place?
If you want to condition a big beer for several months, do you have extra kegs that can just sit there out of rotation? Are there places to put them?
Lastly, there's the issue of space. Not everyone has a place to put even a small kegerator. I've looked in to it myself, and I have no idea where I'd put it. There just isn't room.
Much like the "carboy vs. bucket" debate, the "bottle vs. keg" issue isn't as clear-cut as it seems to diehards on either side. There are advantages and disadvantages to either. I'm a bottler now, but I'd love to get a kegerator at some point... I'd still probably bottle a few from each batch though.