I was going to ask this same question the week I flat ironed my hair and ghee-d overnight to wash the next day.. when I woke up I DIDN'T WANT TO WASH IT OUT
my hair was SO moisturized and shiny (If I used a little less it would've looked better). But it was reeaally greasy and smelt like popcorn.. I don't mind the greasyness because I could've used less, but if you can find a way to mask the smell I see no issue in leaving it in.