What? If used more we wouldn't even need to transform it to any other currency, its because is _not_ used more that it is usually needed to convert it to something else.
>"How would it do that? Why doesn't someone just walk in and take your computer?"
No, someone cannot walk in because he doesn't even know where to walk in, its the same reason Satoshi is extremely rich despite the curiosity of millions to know about him, but no-one even knows his real name or anything at all; we don't even know which country he lives in; so yeah it does replace physical security; at least to a significant extent.
>And if you're concerned about the creation of small computer chips (why would you be concerned about this), I assure you that Bitcoin is using more of them.
It was just an example of the millions of resources that are wasted by the finance industry, a lot that include transportation (gasoline/ fossil fuels which is way way worse than most sources of electricity gpus are using)