Responses
Tho an ending like that is welcome it would be a weird twist for a story which started lighthearted and comic to have a bittersweet ending.
Serin seems to actively search for connection human other than Gi-Tae so much so that she's not thinking of romance at all (zero jealousy towards a woman who is romantically attracted to him). Her ending with only Gi-Tae as a connection to human would be sad imo, even if he accepts to lend her his body from time to time
Y'all keep on pushing that's she'll be human etc, like there's a possibility she's ghost until he dies or until the story ends. Her being a ghost doesn't hinder him having a relationship with her it's just going to seem like he's a loner and single on the outside.
It's entirely possible for them to be together as they are, no need for her to turn into human, if she does, it's a welcomed plotline, if she doesn't, then they can date as ghost and he can be loyal to only her for life