I confess I'm not sure why people are talking about bugs now. I was talking about how hardware can access higher levels of performance and efficiently guarantee more things (eg. early persistence guarantees) than software can.

If the firmware has severe bugs (which is incredibly common with all firmware) and is hard to debug and patch, the performance is irrelevant. Not to mention that there are many examples of existing firmware bugs where the performance of "simple" hard drives tanked -- adding more code to already-buggy firmware that has a history of performance problems is unlikely to improve performance (let alone reliability).

This is a rather different claim to saying there wouldn't be a benefit. I'm not saying filesystem accelerator SSDs would necessarily be in sum a good thing, just that in principle it seems like the kind of thing that should perform better than today's abstractions.

Because the hardware is implemented with software.

You are rather missing the argument. If KV SSDs are much faster than doing the same with a software DB on top of a block abstraction, is that not proof that these are inequivalent? GPUs run software too, but that doesn't mean it's in anyone's best interests to run that on the CPU—not all software is the same, precisely because the hardware is different.