
I’m guessing the variety of tea comes from other countries. Though this country believes tea to be a barbaric beverage, that does not mean that other countries believe the same. It may just be the opposite; coffee to be barbaric and tea to be refined. The variety must come from other countries who believe tea may make them a profit. Or at least want the art of tea to spread far and wide. And then the tea sets. I think the shops have tea sets for one, to make tea for those who like tea, and two, for decoration. I mean, if we think much about the setting. This is an aristocratic European setting. And it seems common to have things that would have use be decorational purpose. You know, like a vase without flowers. Some of tea sets may be made by popular craftsman. So those who want to collect art pieces from popular craftsman may pay just to have the item in their collection. They may not use it, but it’s something to boast about.

Well it's probably either they've actually have people who enjoy tea before the current duchess reincarnated or because the tea was transported from different countries or maybe cuz it's a manwha and the author be like "okay, since it's 'bout tea Imma just study and put a lot of different kind of teas in the story cuz that's what it's about" I dunno it could be anything

I think the latter reason might be true. But it probably would be a little less weird if the shop was in another country or a little harder to find or the duke specially order crafted for her. It was just too obvious that there is a particular shop just for tea sets and tools in a country where no one drinks tea. How are they even doing business?
Not to mention it was a well crafted, expensive tea sets; not some cheap things.

It was transported from other countries. The "barbarian" countries. In one of the chapters, the women discusshow a large amount of tea goods came in along with coffee, which is rare. Also, for the shop, you could see that compared to the coffee goods, the tea sets were simple looking. They live in the main city, so they will mostly everything they need. Also tea is still drank in this country, but it's just not popular among nobles (like it should actually be in real life).
I am sooo confused. If their country think that tea is a barbaric drink and no one drinks it, then why do they have SOOOO many variety of teas? not to mention they have a shop just for tea sets??
I mean we are a tea drinking country. We drink tea like we drink water but even we dont have that many variety of teas. We have maximum 10 -12 types of tea AND we are one of the top 10 tea producing countries in the world!