There are lots of different kinds of "chips". Some just alter the mass air flow sensor or water temp sensor readings, others allow a completer reprogramming of the fuel and spark curve, and can have multiple, switchable programs. Obviously, the results will be similarly all over the map.
Stock programs need to account for a lot of issues that may be encountered, bad gas, varying weather conditions, varying load conditions from towing or hauling, plus whatever else might happen. Based on this, there is room to optimize conditions for a particular weight of vehicle, type of driving, etc, but you don't want to give up the capability to allow for outlying conditions that could cost you and engine.
If you are willing to spring for one of the chips that allows individual programming for multiple conditions, you could probably get some overall benefit in at least some of those conditions. Maybe one for low altitude flat lands, one for climbing at high altitude, one for power, one for city, one summer one winter, etc, all switchable. Those setups aren't cheap or easy to program properly, so ROI is very, very, shaky on them. Add to that the fact that if you mess up and have lean mixture and/or too much timing when climbing a mountain, it could perforate a piston or burn valves.
As a hobby, it could be entertaining and educational, as an improvement to day on day driving in a van, probably a money loser.
IMO, for a driver, I would pass.