I understand how it can achieve better performance by bypassing the file system. But I'd like to compare this to hypothetical key-value software that stores it

I understand how it can achieve better performance by bypassing the file system. But I'd like to compare this to hypothetical key-value software that stores its data directly on a partition (instead of in files). Isn't this essentially the same thing? The only difference that I can see is that the software would be much harder to update, and you can offload some CPU on to the processor on the drive. Am I looking at this correctly? I don't get why you would want this to be a hardware device.