I think, and I'm just guessing, that you condition at room temp to let the yeast react with the dextrose to carb your bottles.
That said, if you don't need to carb bottles, you're ok to condition in a keg?
Yes. But some beers need some time to condition, while some don't, and beer conditions faster at room temperature.
As an example, say I have two beers that are done fermenting. One is a 1.040 OG mild, and one is a 1.060 stout. They finished fermenting at day 5, and stayed in the fermenter until day 10. They are ready to keg.
So, I keg the mild and since it's not a complex grain bill and it's a lower OG beer, it's ready to be chilled and then served. But my stout has black malt, and roasted malt, and it needs a bit more time for the flavors to meld. It would be best at room temperature for a week or two for that to happen, and then placed in the kegerator. It really depends on the beer.
Most simple beers are ready early. Time to ferment out (up to a week), and then a few days after that to clear a bit. This assumes that the proper amount of yeast was pitched, and the beer was fermented at an appropriate temperature. If not, and off-flavors were created that may take more time to age out.
A well made beer can be ready to be served shortly after it is fermented out, usually. Some "bigger" beers like barley wines and Russian imperial stouts would be exceptions, of course.