I can make a glorified cardholder, or microminibag as fashion would dictate it, work if I hold my phone in my hands. Some days I do that and gush over my silly excuse for a bag. I have wallets bigger than some microminibags, but I adore them. There is not an excuse needed if you really love something. If you really love this bag, you will wear it because of how it looks. If you want a practical bag, you already have your mini square.
Personally I don't think this differs too much from a mini square and it is a lot of money. Keeping your phone in a pocket or your hands is a whole other level of commitment. You say you want to wear this as a special occasion bag, but do you really want to hold your phone in your hands on those occasions?
The best tip I can give you is try to hold your phone in your hands and see if that is something you can live with. If it already bugs you at noon, just the pearls will not justify buying this bag. If you still love the bag even after all of the hassle, then it will be worth it. Not every bag has to be practical but if a bag is not practical, just make sure you love it instead of just want it.