I've never been a super fan of Hallmark stuff, but I did actually listen to (I think) a podcast featuring someone who otherwise appreciates more serious entertainment.
The way she described the elements that appealed to her, she sort of sold me on the concept. Everything's ridiculous with holiday decorations, you can basically identify all the same formulaic characters, you know they'll find love, nothing bad will happen.
Basically it's all like the part in the movie Companion (which is amazing) where the "companions" all have these formulaic "meet cute moments" implanted into their origin stories.
Like, I've never been into Gilmore Girls but I can definitely see the appeal. There are like hundreds of holiday Hallmark romance movies and if you like one christmas cookie you can enjoy the rest of them without skipping a beat.
I enjoyed Krampus myself (the first one)