However, it is very easy to install schrader valves on soda pop caps, and very easy to make up a chuck-to-ball lock (or chuck-to-pin lock) connector too. They can't stop you from DIY if you aren't selling them.
I did this years ago, maybe even before I had kegs. I still use the caps on a somewhat regular basis.
I also put some quick disconnects on my gas lines so I can swap off the ball lock connector for the chuck super easy.
I don't remember the price of the tire valves, but you can pick them up at NAPA pretty cheap.
The best thing (which I learned from a post from Denny) is to fill a liter bottle when you're kegging, blast in some CO2 and toss it in the freezer for 30 minutes. Instant fresh carbonated beer. Maybe I'm impatient, but it's awesome to sample it so quickly.