I also don't mean to put down the creators of this product, it probably has its use cases. But every time I see something like "SQL with the scalability of KV"

I also don't mean to put down the creators of this product, it probably has its use cases. But every time I see something like "SQL with the scalability of KV" (which happens a lot these days), it's like someone promising a perpetual energy source. In other words, there is usually some kind of catch involved. In this case it's that JOINs are still expensive. Well, this is actually a pretty big deal, because JOINs are typically the reason I settle for either a NoSQL or a SQL store. Again, I'm sure this has other merits that may distinguish itself from the rest of everyone and their grandma building a database these days.