I bought my keg gear years ago before I even knew what AG brewing was all about. I guess I managed to brew a reasonable beer to put in them, one that I was happy to drink anyway. I guess it comes down to if YOU are happy with the kit beers you brew. Kegging them won't improve the quality of them, nor will it lessen it, it will only take some time out of the process e.g. bottling, carbonation etc. and as previously mentioned, maybe clear up some space. On the other hand, there really never is an end to bottling. If you want to swap beers, send some off for comps or feedback or you run out of fridge/keg space, you still end up bottling.
When I decided to try out AG, it really cost me bugger all to start up on the super tight arse regime to
1) see if I could do it and
2) see if I liked the beer any more than my kit beers.
I had a 45L esky already and it only cost me $25 at bunnings and I had a mash tun. I bought 2 cheapo 20L stainless pots which doubled as a HLT and Kettle. I would mash then do a split boil on a camping stove and combine both in the fermenter. All in all it cost me no more than $150 to get going and I found I was immediately impressed with the results. The beer was way better than my kit beers were. The money isn't wasted either, because I still use the esky as I haven't had time to build my other tun yet and even though I've graduated to the big arse burner and 80L kettle, I still use the smaller pots for decoctions etc.
So I guess its a trade off as to what you think you want to achieve first. If you are really happy drinking your current beers, go the keg system and maybe speed/tidy up your process a little. If you really want to give AG a go in the hope for better beer, do it super tight arse fashion or maybe see if you can make a new buddy that already does Ag and do a brew day on their gear for the small fee of a few beers to see if you like the difference enough to go the whole hog.