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.