I'm actually more likely to carry my H bags than my mid-range bags when traveling.
Said mid-range bags are mostly Longchamp Pliage Cuir S in various colors, and I know that they could be unclipped and yanked away from me. (This only occurred to me when one unclipped and fell all on its own initiative!) I also have the unthinking tendency to let a cross-body bag fall behind me where I can't keep an eye on it. Fine in my own city, not so much elsewhere. The H bags (Trim and Yeoh) and BV bags (Veneta) are under-the-radar, have integral straps, zip securely, and sit firmly under my shoulder.
I usually carry my purse in a larger Pliage during actual transit, a bit to protect it but more to stuff in all the other transit-necessary bits and pieces. Backpacks can be more practical, but again I don't like having important things behind me where I can't keep my eye on them in a crowd.