FeFETs are planned for embedded non-volatile memory, eg. the memory for code storage build into microcontrollers, not SSDs. In current devices this is typically NOR flash, and the code executes directly from it. There's no pool of empty blocks, but the cells are single level so endurance is still acceptable.

The FTL (a sort of mini log structured file system that runs inside your SSD), works very hard to try to smooth over flash's erase block requirements. That said, it's far from a panacea, and many applications would be much simpler if they could just do real random writes to the physical medium.

Take a look at https://www.usenix.org/system/files/conference/inflow14/infl... for a nice summary of what issues pop up even for applications that make all their writes sequential.

I think it does; while theoretically the storage driver should maintain adequate empty blocks, often they don't - see reports of "SSD performance degradation".

My guess is that it should help with performance on full SSD drives and when there's a lot of small writes that burn through the pooled erased blocks.