A Dremel tool is not an absolute necessity. Kits were built long before Dremel was around. They do make some things easier and they save time. If you are happy using simple hand tools and get good results then by all means stick with them. The planes you have listed probably wouldn't see much use from a Dremel anyway (helis, ARF's and foamies). I have one I have had for 15-20 years and I use it all the time and not just on planes. They aren't the solution to everything...I still use the good old razor plane, sandpaper and files when building.