The point of Monaco, IMO, isn’t the actual race at all. It’s about everything around it. The money, the yachts, the showing off. Monaco is what establishes F1 as a ’glamour’ sport to people who don’t actually know much about or in fact care much about actual motorsport.
It has a lot of ‘brand value’ as an event even if in terms of being an actual race is almost always a disappointing spectacle.
At least, that’s what I suspect the people pulling the strings believe.