It’s interesting, however, if you mkfs.ext4 without -E ssd, or through some weirdness in your driver chain the filsystem doesn’t know it can discard, then everything everywhere sucks for everyone, a cow fs is worse because no blocks are ever overwritten till the end, and the block map becomes a disaster while performance goes down the drain.

Nowadays this rarely happens outside of very broken USB mass storage chips.

This is why we used to have the fstrim command.