Seems like if Lore wants to reduce space usage, they could apply something like Git's delta compression (as used in packfiles) to the chunks.

Suppose you make a 1 kB change in a 50 MB file. That causes a 64 kB chunk to be created and stored. Disk space is wasted.

But since the 50 MB file was already stored as a sequence of 64 kB chunks, there is an existing 64 kB chunk that is very similar to your new 64 kB chunk. You can store your new chunk as a delta to that, so only ~1 kB of disk space is used.

Admittedly, it's complicated and inelegant. But it allows both deduplication between files (one of the reasons Lore chose chunks, apparently) and efficient space usage for small changes.