Physical stuff has its own advantages against the digital assets. For example, it is very difficult to steal physical stuff. But it is relatively easy to steal Bitcoins from someone who is not that tech savvy.
Or maybe having a physical form is actually a disadvantage? That means someone can take it away from you or snatch it from you. The same way how bitcoins can be stolen from someone who's not tech savvy enough, anything physical can be stolen from someone who can't defend himself physically.
I actually think that bitcoin is even much safer because an average thief only takes fiat money and other valuable stuffs at your home. If he sees a piece of paper with a combination of number and letters written on it (your private keys), he would just think it's some kind of rubbish and don't think that it's associated with money.