Using kegs is SO much nicer. Things like:
- No need to clean, sanitize, and fill up a bazillion bottles. Clean the keg, sanitize it and just rack to the keg.
- You can use a keg as a secondary/conditioning. I go from my primary (plastic) directly to the keg for conditioning.
- No worries about oxidation when racking. You can co2/vent/co2/vent/co2 after racking to get the oxygen out of the keg.
- You can use the keg even if you want to do bottles or mix/match. For instance, I sometimes rack to the keg but first put my sanitized sugar for carbonation (sugar + water boiled for 15 minutes) in the keg and then rack to the keg. Then I do some bottles from the keg (using a small amount of co2) to the bottling tube and fill up some bottles to bottle condition. Then the rest I just leave in keg to naturally carbonate.
- You can use the keg and use co2 to carbonate, and then still do bottles as desired. See
https://www.homebrewtalk.com/f35/we-no-need-no-stinking-beer-gun-24678/
- You can quick carbonate if really needed. I don't recommend this as it is easy to overshoot your carbonation level, but it can be done if in a pinch.
- You can change your carbonation level if needed over time.
- You can use the keg to "cold crash", then remove the crud by just drawing a couple pints. (Only gotcha is that it is possible to clog the beverage tube - I managed to do this once....then you have to remove the tube, clean it, sanitize it and put it back.)
- You can leave the crud (but don't drink it) by shortening the tube a bit or bending it.
- You can have soft-drinks "on tap". Make your own root beer or cream soda or whatever for the kids. (I tend to just make carbonated water that can be mixed with a cream soda or other solution that i keep in the refrigerator).
...and so on, and so on