Inedible usually just means unpleasant tasting, not poisonous. A good example is the
coyote melon . They are much too bitter and soapy tasting to ever think of swallowing any.
But they can still be useful. Even if the flesh is nasty, the seeds may not be. You can roast them to make pepitas or press them for oil. And if the oil has an off taste, well, at least you can make soap out of it.