The bank accounts are traceable and insured, though. If I use a $5 wrench attack on you and get your bank info, you can reverse the trade afterwards. And that bank account I transferred things to can also be traced and tied to me. If I instead use your ATM card/PIN that I've beaten out of you, that'll ensure I'm on camera.

OTOH, if I get your wallet info and transfer it to my wallet, it's traceable, but not tied to me. Now, getting it to a point where I can use it without giving away more info may take work, but it can still be done.

And on a meta level, there's simply the perception of btc hodlers as having tons of it, so the hypothetical robber is much more likely to go after that guy in a btc hat because he assumes the guy's got thousands of btc, as opposed to a "normal" amount in a bank account. It doesn't matter if he's mistaken if he still beats the crap out of you.