Continuous writing to the same area on the drive can probably exhaust the spare cells and degrade performance. I don't know how the firmwares deal with 0 spare cells and further failures, though.
I have a swap partition on my SSD but I also have swappiness=0, so that it only writes to disk if there's actual memory pressure.
Modern SSDs use wear leveling to prevent this from happening. If you write to the same logical location a thousand times, the SSD's wear-leveling algorithm will write to a thousand different locations.
I have a swap partition on my SSD but I also have swappiness=0, so that it only writes to disk if there's actual memory pressure.