Back when I was first starting out, I made a somewhat similar mistake to the one you just did. I even posted my opinion about it in this forum. Years later, I’m now confident that you’re wrong, at least in part. It’s true that many people could theoretically manage to memorize 100k. Many, but nowhere near “anyone”. And it certainly isn’t easy. You can’t just extrapolate from what you can do in 5 minutes or what someone else can do in an hour and perform a simple multiplication. The amount of reviews that are needed is insane. Your brain needs time to change and durably incorporate all those new stories into your long-term memory. Even with your extremely high skill level, I’d be very impressed and quite surprised if you could make it to 40k with perfect recall within a month. You probably would make it to 100k eventually, but it would take much longer and be much more difficult than you seem to think.
My personal answer to the original question: 10s cards is more impressive in a way because it has never been done so far. Such a feat would require a lot of skill and perseverance, but also some rare form of talent that I and most people certainly don’t have. On the other hand, I subjectively still prefer 100k and I think it’s much cooler ( : Perhaps it’s because I admire grit and determination and perseverance even more than I admire other types of feats.