It's all good fun. Once in a while, it's nice to read a story that doesn't require much braincells or emotional investment.
That being said, here's a take:
Part of the reason this is good is that the FL is in fact, dumb. Not once was she described as smart. It even specifically states that she focused only on training how to fight for 200 years instead of studying.
Being an angel, it's understandable she would think the ML would reconize her because 1) her common sense is set at a different standard. she just assumed he would also "sense" it was her just as it's natural for her to sense demons or marry Rishar just 'cause she declared he would be her mate. 2) she has no romantic experience.
She's no regressor or transmigrator. Just a dumb little romantic muscle-head who wants to find a husband. That's cute in it's own way.
(this doesn't say much on why the other characters are dumb, but let's just establish this story won't have a super serious vibe. We even have an ML who legitimately wants to have a shoujo-manga soulmate meeting like his parents. this is romcom alright.lol )