Not much to add beyond what Bob and ttabbal said. Just wanted to help you visualize how your tooling changes will work. Anytime you have to change out an R8 collet you have to loosen the drawbar, tap the top of the drawbar to break the collet loose, completely unscrew the drawbar and then drop out the R8 collet. Then you put the next R8 thing in the spindle, insert the thing that goes into the collet and then tighten the drawbar. This is why a power drawbar has so much appeal; it makes this process so much faster. As noted, removing tools and collets require a lot more room in Z, which may mean you have to crank down the knee before removing the tool/collet, then crank it back up to resume work.
Tools will usually have either an integral R8 shank or a straight shank. If it has a short straight shank then you can just loosen the drawbar, drop out whatever tool in in there and insert the next tool if it fits the collet that is in the spindle. Say you decide to put a straight 1/2" shank on your fly cutter and drill chuck. With a 1/2 R8 collet in the spindle, switching from the fly cutter to the drill chuck simply requires you to loosen the drawbar, tap it to loosen the tool, the tighten to install the new tool. Very fast and takes very little room in Z. This is what Bob and Travis were saying.
The reason I like and use the Tormach TTS system is because most of the tools I use on the mill have TTS adapters that mount the tool into a 3/4" R8 collet. I can go from a fly cutter to a drill chuck to an ER-32 chuck in seconds, without having to move the head/knee because the shank of the tool holder is only about an inch or so long. Loosen the drawbar, tap, change tools, tighten the drawbar. It takes all of 10-15 seconds to change tools. There are faster, more accurate systems to be sure but not at the price of the TTS system.