Yes, that's pretty much it, and it's not just Steem - all coins siloed on Bithumb with high prices (Ethos, Stratis etc) have seen similarly insane increases in volume. This is not without precedent, the same thing happened at the end of July. In fact, the volume increase there was far higher.
Exclude Bithumb and yesterday's trading has had no statistically significant impact.
I think we have to be wary of getting excited over false signals. I still hope this blast has made many more people aware of steem