The main issue with premium culture is that it's not upgradable. You buy it and forced to sell it after a chapter or two. It's simply overpriced for such usage even if buildings are good by their own.
Absolutely with you on this one.
When I had achieved a first decent amount of diamonds in my first city a few years ago I was looking up those premium buildings because I thought it could be "cool" to have one.
But not being able to upgrade those in any kind made me think that this were only for them humans and elves who like to support InnoGames regulary, so that they can afford buying new premium event buildings every chapter.
I was always wondering why they didn't implement an option to be able to upgrade those at least maybe a pay-only-option of any kind.
This way they would have maybe been able to sell more of those premium culture buildings I guess.
I mean nearly everything is about upgrading and/or can be upgraded in Elvenar, to me it always seemed like that the fact that this option was and is completely missing at his point of the game took the charm out of those premium culture buildings.
For me, who was always and is still only spending diamonds that were won ingame this never seemed to be a worthwhile option.
Luckily, with the arrival of Eldian Sapphire I will soon be able to fulfill some old unfulfilled dreams from the past!