The drive internally usually stores data in blocks larger than the 4k blocks it pretends to use to the OS (say it uses 16k blocks internally). So if your writes are sequential, it will most likely write the same 16k block in one go. If you write random 4k blocks, it will have to rewrite a full 16k block for every 4k block you write, hence write amplification.

So if you fill the drive over and over using sequential writes you can expect way more endurance than if you write random blocks.