Even in China they have always used saucers.
What about in Japan? I have a generic Japanese pot-&-cups set, and it did not come with saucers. It isn't a traditional set with the whisk and other accoutrements, as I don't make my tea from matcha. All it has is a raised bamboo board on which to place the cups—a "coaster" more than a saucer.
- The
gaiwan is Chinese.
- Japanese
matcha tea is served in bowls, not cups.
- Japanese
sencha tea, on the other hand, can be served in cups with saucers.
I have a traditional Japanese
sencha set that I bought from Japan on ebay which came with matching cups and bronze saucers. Sencha cups don't always come with saucers, but these did.
Mine are very similar to these:
This is a tea cup saucer of Japanese tin ware. This was made about 120 years ago.
This is old original. It is never imitation.
Such a tea cup saucer is mainly used in green tea of middle grade SENCHA.
Social status is high and a SENCHA tool is very popular.
This has an old good tin taste. It is just a Japanese antique tin ware.
And a design is a also very tasteful. Of course, this is handmade by a craftsman.
There is a maker's sign.
This is the very good old SENCHA-tools seriously made by the specialist.
Please purchase at this opportunity, and add to your tea utensils collection.
I think Markus' essay makes good points, but aesthetically, those ornate floral European teacup patterns are not to my liking, even though they have a sentimental value to me, as my Irish grandmother always served tea in patterned china (with saucers).
I inherited a number of beautiful European tea items from my deceased aunt, and over time I have come to appreciate more and more the aesthetic they represent.
But there is a comparative austerity and minimalism to Japanese tea sets that I prefer over the European, especially the ones with script on them. I also like the absence of a handle: you know when your tea is at drinking temperature when it doesn't burn your finger.
I have always been a nipponphile, and I bought a large number of Oriental tea items from Japan and China through ebay and other sources. Tea, after all, comes from China. But the more you study it, the more you realize that a lot of the aesthetic was borrowed from Westerners by Japan.
Also, the Japanese aesthetic is not really Zen minimalism. It's something else called
wabisabi.
Wabisabi is something that is very difficult for Westerners to appreciate, and maybe for good reasons.

Here is the ultimate manga of all time that studies the Japanese tea aesthetic within the context of the
sengoku (warring states) period. It is both hilarious and very informative.
[Warning 1: Some adult material in the manga.]
[Warning 2: I use ublockOrigin. I don't know what kind of ads you might see if they are not blocked.)
https://mangarock.com/manga/mrs-serie-111668
It was the Sengoku-era, when the warlords usurped each other. There was a man whose soul was overtaken by the ways of tea and material greed, as he worked his way up toward greater power and status. His name was Sasuke Furuta, a subordinate warrior of Nobunaga Oda. With his world broadened by Nobunaga the Genius and his spiritual insight learned from Senno Soueki the Master of Tea, Sasuke drove the road to Hyouge Mono. To live or not to live. For the power of the art. That is the question!