It’s a pretty niche thing, makes more sense for Max users. The eurorack modules were designed for 128. 256s generally sell used for about $900-1000.
As for “was @tehn serious?” I think he’s aware that it may be difficult to get the count much higher than the 10 we have so far on this thread.
Hence, the motivation to explore the new thing. And you’ll soon learn that @tehn loves to tease us.
If you do eventually get the itch to acquire a 256 (I recommend starting with a 128 and then experimenting with Max programming with the grid to decide if you need/want more) it should be mentioned that only the 2012 edition has 16 levels of variable brightness. (That’s the batch of 50 I’m referring to). There are other editions that had 4 levels of variable brightness, or mono-brightness. They are far more common (but much less interesting to me personally).