because theres been lots of success stories from previous adapted live action and its a more time efficient choice
1. you basically the big plot written already so the screen writer only need to tweak some of the plot rather than writing it from 0
2. easier to promote as the manhwa story got fans already most of them will probably tune in to at least watch the first episode of the live action

I don’t understand why there are so many k drama adaptations of romance manhwa lately. I don’t appreciate it at all (づ ̄ ³ ̄)づ. As a lover of both comics and k drama, some stories are better left alone ┑( ̄Д  ̄)┍. Leave my babies up to our imagination ╥﹏╥