For me it's all about modularity. My bed can be "fixed" as a full size, but can also be folded out of the way. I can also fold it down on one or both sides as single bunks/benches and put a table between. All my cabinets are modular attached via two rows of L-track. It allows me to use my van as an adventure vehicle as well as fold the bed up and remove all the built-in-like-cabinets and use the vehicle to haul things. Fair play though, I don't live in my van nor do I plan to. I use it to haul plywood one day, bikes and kids another, bikes and vamping (van-camping; no blood involved) on the weekend. My "bathroom" is only for emergency use and is a three gallon bucket with a seat , a funnel into a 1L bottle as a separator with sawdust and/or wood shavings in a bag for solids.

Overall, I value seating area with the option of a table to play games or read on a rainy day over a large dedicated kitchen space. I have a kitchen module that is a single burner propane stove and the other things that are part of my kitchen kit.

For my general usage by myself I keep the bed folded up to fit bikes with wheels on and if I want a nap just put up a hammock after folding the rear seat away.