Hmm I have not heard the specifics of the one where it matters so much that one does not need a spellbook. If it just saves gold and hastle it seems a bit much of a hastle for having to make miracle an illusion spell.
The other bit is of course still problematic as ever due to the undefined term in assume supernatural ability means that the trick is again completely dependent on the DM ruling (as just because things sound similar does not mean they are the same).