Correct, if you are trying to utilize it for a sole method of heat and cool. You will still need to dump excess / add additional through more conventional means

Correct, if you are trying to utilize it for a sole method of heat and cool. You will still need to dump excess / add additional through more conventional means, depending on local climate. To your underlying point, none of the added complexity is worth the effort unless a) the utility is paying you to take the excess load and/or b) someone really innovates on a slick, simple package.