What is ugly? A tank covered in algae where young fish can hide and grow up? No plants? Full of plants, leaving almost no room to swim?
I think it's always about the fish. What do they need, what meets their requirements?
An aquarium without plants can be perfect for Malawis, but for some bettas, the green hell is, but not the other way around.
In my experience, creepy decoration is often combined with poor fish keeping - inappropriate size, fish that don't fit in and don't go together, one-sided feeding and so on. And by that I mean both sides of the spectrum - poorly maintained aquariums full of plastic stuff and aquascapes whose sole purpose is to represent a certain land(!)scape.
And what I've learned here is that it's also a cultural thing. When I see an aquarium with artificial plants in my neighbourhood in Germany, I can say with almost certainty that something else is wrong. We only know aquariums without plants for Malawis and such, and even there, people plant something because it's so unusual to have an aquarium without live plants.
It's different here. But I sense that there's a movement towards more planted aquariums, right?