The answer to why is the same as most others who have done the same cost and built to satisfy own requirements. The second "what for" a little harder to answer, At present My wife and I [empty nesters ] have a B class van ,a boat and a teardrop which we pull with a 3cyl car all are good for short stays but just a little to small for the longer trips we are about to start taking. We want a lite towable home away from home that will utilitise our set or portable appliances that move now from boat to van. The solar
panels,house batteries, hot water system, freezer. and heater. There are more but you can get the picture. Also doing it will be a challenge.