They both portray strong female leads (in both senses of the word)

It has the same concept and you get to see the main character interact with each of the main actors on a personal/romantic level.

We have of course Kai as a protagonist in both dramas and it's just as quick and easy to watch. Both cater to quick paced/ short romances.

Besides having the wonderful Jun Ji Hyun as a main character one again, both dramas explore mystical being and "past lives".