I've been to Europe a few times and didn't even bring my Kelly with shoulder strap. I can't imagine lugging a Birkin around if it's a sightseeing trip. Too bulky and heavy. I have an Evelyne and would bring it in a heart beat next time. Here's how I manage the open top issue: I have a LV pochette, which I clip to the Evelyne strap hardware loop to keep it secure and prevent it from falling out or being taken. Inside the pochette, I keep a small wallet, keys, and anything I don't want stolen. Then in the rest of the bag, I keep a makeup pouch with all other makeup and small accessories. Nothing small is sitting freely in the bag. I've done other travels with the Evelyne and have never had a problem. It's lightweight, holds a small umbrella and water, and still looks chic when you're out shopping.
The Jypsiere is gorgeous but I think it's still too heavy and the closure can be a pain. When you're traveling, you want to be in and out of your bag quickly and easily. You could then bring another smaller H bag to bring out at night.