Having worked on firmware writing to SD cards, I can tell you that the big problem comes from allocating space for writes. That’s when the card disappears on yo

Having worked on firmware writing to SD cards, I can tell you that the big problem comes from allocating space for writes. That’s when the card disappears on you, as it looks for space it will potentially shuffle data around behind the scenes. Current spec I believe says max latency is 200ms. This is the operation that will abuse this part of the spec. If you want to see an SD card flail, just try to write one byte at a time. This will cause headaches no matter how wear leveling is implemented in the SD card. And will likely significantly shorten the lifespan of the card. If you can make sure you only ever write multiples of 4096 (probably card dependent) you’ll be much happier using SD cards. But even then, you might have a 200ms window where you can lose or corrupt data if your power to the card fluctuates significantly.