I'd say it makes checksums even more important so that you know whether something got corrupted immediately and not after a year (or whatever) has gone by and you actually need it.

The problem is that if the SSD suffers a power failure and reverts a 1 megabyte block of metadata to the way it was yesterday, the filesystem won't see that as corruption - since all the checksums will match.

Yet all the pointers in that metadata will point to data which no longer exists, and your filesystem will be destroyed.

So... metadata checksums? I mean if enough data/metadata gets corrupted you're SOL either way.

For example, in ZFS the metadata is checksummed such that pointers to the data carry the checksum for that data.