This certainly could be just marketing fluff in top of nothing more than a regular SSD being put into the machine, but I will wait and see before calling it just that. What has me really curious here is that even though they did cherry pick a game that already has really quick load times so that they could achieve a load time less than a second, they did so by a 9X increase in speed. Out of curiosity I looked through several video comparisons of games loading on SSD, and while there were a few bad ones that only got a 1.5X boost, the best range was around a 3.5x boost. To me this says one of 2 things. Either there is some special hardware solution, or (this is sort of answering your question), this game was modified to run differently so that it could load faster.
And even if your SSD allow for a faster load it doesn't allow for a faster traverse time.
duduspace11 "Well, since we are estimating costs, Pokemon Red/Blue did cost Nintendo about $50m to make back in 1996"
Mr Puggsly: "Hehe, I said good profit. You said big profit. Frankly, not losing money is what I meant by good. Don't get hung up on semantics"
Azzanation: "PS5 wouldn't sold out at launch without scalpers."