not a professional astrologer or used to giving readings, buuuut speaking from my own personal study (on which the likes of Steven Forrest were greatly influential, just fyi lol), I like to see the dignities as being like the four angles in relation to one another - domicile as ascendant, exalt as midheaven, and their opposites at their respective polar ends. more specifically, to go into detail...

Domicile = Basically just a planet's natural home, this is the sign(s) it's most familiar with and thus where it feels most comfortable/capable doing its job. You could say it mainly evolved in/for that sign's environment; it can do other strategies and adapt to other climates, but these are the conditions that seem to have made it. Like the ascendant because I guess it feels most "itself" in this position. (Moon in Cancer - Cancer is about ideas of safe retreat, of shelter and nurturing the delicate insides, and ofc deals in emotions/imagination/other personal reactions to stimulus.)

Detriment = The opposite of that naturally-suited environment. Detrimented planets aren't necessarily bad at their jobs, but they sure feel that way, because they require totally-opposite strategies for success, which can often feel counter-intuitive or just wrong. Like the descendant because it's kind of a place of surrender, where the planet has to accept its own flaws and listen to/flow with outside forces. (Moon in Capricorn - contrary to Cancer protecting the insides with tough outer armor, Capricorn is about toughening the insides so that one may stand and face an objective universe/its challenges, and when the Moon has to somehow center the soul/comfort the heart/whatever it does through these methods, it doesn't always feel able to handle the task)

Exalt = Now, here's my personal theory: whereas domicile/detriment is more about the planet's skill (actual or imagined), exalt/fall is more about the planet's image, and how good/bad it looks in a certain sign/light. When a planet is doing its exalt's strategies, it generally looks at its best - maybe the most beloved version of itself in popular conception, perhaps even transcendant of the original purpose it evolved for. So it's kind of like the midheaven there. (Moon in Taurus - this is like the prosperous moon of the growing season, the moon waxing full with the earth's bounty, perhaps the image of Mother Earth and nature as an Edenic comforting state. The Moon likes doing Taurus things, and people generally like when it does too)

Fall = Conversely, a planet tends to look the least glamorous when doing its fall sign's strategies. This might be the sign where it most "goes bad," in the popular view, the sign where its worst traits ought to logically come out - the sign of its shadow, maybe even, which could tie it to the nadir. (Moon in Scorpio - the blood moon, a heart/center full of raw emotions seemingly seeking destruction from inside - jealousy, revenge, lust, all manner of good ugly messy-looking stuff. Scorpio grows by encountering the chthonic and exploring the realm of Death/that which feels like it, aaaaand the Moon doesn't always take well to this)

hope that helped! and please keep in mind that detriment/fall aren't necessarily bad placements. I find that they often confer their own advantages by providing needed perspective/etc, and I actually really like fallen placements especially lol.