I'm not sure why people have to be rude when a genuine question is being asked or pondered...
As somebody else stated, you have to find what's right for you. Personally, I worry more about general pickpocketing than RFID threats or being dragged. I had a Pac safe backpack that I wore my first time to Europe and Russia and I am convinced that it saved me more than once from pickpockets. I called it my personal Fort Knox. Somebody who is determined to get your bag- will, but for instances of general pickpocketing, why make it easy for them? My daughter and I were on the subway in Paris when a group of average looking teenaged girls started shoving me (personally) and others on the train, shoving my daughter off as they shoved me on. In that moment, my fear was losing my daughter and as I reached behind me to grab her I found myself in a shoving match with one of the young girls. Just as the doors were closing, the girls gave a final shove and ran off the train. My daughter had a bruised wrist (from me) but got on to the train. The man and woman next to me lost their wallets. I lost nothing.
When I went to Europe again two years ago, I had my backpack and also a Pac Safe crossbody bag (I wanted something smaller than my backpack for most days and I dislike the feel of moneybelts and neck wallets). Again, I was witness to two separate pickpocketing incidents (that I'm aware of), both in Rome, one at the Coliseum and the other on the train getting there. One guy lost the contents of his back pocket (fortunately his money and cards were in his moneybelt). The lady being picked on the train was actually saved by one of our tourmates who saw it first. The victim was a woman wearing a crossbody purse right in front of her, in her hands, but we were packed in like sardines and she was looking around and the thief was ready to take advantage. She had the victim's zipper open and her hand inside when my tourmate saw her, slapped her hand and started scolding her and "tattling" on her to the other passengers as loudly as she could. The thief got off at the next stop as the victim was still processing being "picked" with her purse right in her hands.
So for me, overkill or not, I don't care. If somebody wants my things, I'm at least going to make them work darned hard to get them. As far as being dragged by purse straps, that's horrific. It's also, unfortunately, something that could happen should you be holding anything grab-able. Find what works best for you and gives you the most comfort. I love my backpack and crossbody bag and they'll be going back with me to Europe in September.