Let me start off by saying how annoying it is to have to switch wallets in order for it to fit into a bag. I don't like switching wallets because I always end up leaving something important (that I don't think it is) in my other wallet. Unfortunately, my Dionysus is one of those few bags I don't like using for that exact reason. The bag is structured and flat and has a pin closure, which means you shouldn't put anything too bulky or else the bag won't close. And in this case, my wallet was the bulky item. You're also going to want to set aside bulky sunglasses (and don't bring the case) and portable chargers. What will fit are things like makeup, notebooks, or even an iPad (except it can get a little heavy).

The chain strap can be easily pulled into a top handle (double strap) or leave it as a single strap to wear on the shoulder.

The Dionysus comes in three different sizes:

• The one I have is the regular/medium size; $2,250.
• The interior is cut into thirds with a middle zipper compartment. There is also another compartment underneath the suede flap and an exterior pouch on the backside as well. 
• The next size down is also a shoulder bag, but a smaller version; $2,100.
• The smaller version contains the same features as the medium, but the whole bag is cut down by an inch (length and height; width is cut down by half an inch). 
• There is also a baby Dionysus; $1,550.
• This size is more comparable to the Chanel Extra Mini Flap than the Céline Nano Luggage Tote. Again, because the bag is structured, you can only fit so much. Moreover, the suede sides are accordion-like, which already takes up some space. Here's a photo from the Gucci website to better illustrate that point:
  
  What I do like about the mini version is the strap. Not only can the strap be used as a shoulder strap or a top handle, it can also be used as a crossbody strap.