[development] Why is Block table delta field only 32 chars?

I spent a good long while trying to figure out why my 38 char delta block would show up in the admin_display but would not get assigned to a region. I realized that UPDATE ... WHERE delta= "full 38 chars" was not going to find my truncated entry created by _block_rehash :( Is there a reason to limit the length of this field? Should I submit a patch to check for this in _block_rehash and alert the user? Best, Jacob