If it was me, I wouldn't use em for the type of data we put in, but since I'm not in charge...
They do make it a pain when you try to query tables, using one of the blob's fields as a key. I.E. I want a list of all leggings, wearable by warriors granting a bonus of between 20-50hp. You have to parse through the data instead of letting the SQL engine do the work.
Of course, that doesn't matter for the Emu, but makes a big diff for those making 3rd party apps.