Break in, bash owner about with a wrench, get coins. <Insert xkcd>
The people that did exactly that never had to worry about (hyper)inflation...
Oh but hey, checkmate, burglar who is threatening to cut my daughter’s finger, my wallet is multisig !
Gold is interesting because more of it was being mined and produced all the time. There wasn’t even a finite amount of gold.
Thinking that a gold standard means no inflation (or in practical terms, deflation as the population grows) is a modern fantasy.
There are ways to prevent this. Like using multi-sig with geographical separation (so you can't move funds alone) or setting up forced time-delays. Ultimately, being your own bank is a massive responsibility, and I think too many people take that reality too lightly.
It’s the same logic as iPhones bricking themselves after being stolen. Even if your specific phone isn't an iPhone, the fact that most phones are now useless to thieves discourages the crime across the board.
Our knowledge is constantly expanding, allowing us to build things differently than we used to. Modern cryptography, which makes things like multi-sig possible, is only a few decades old; it didn't even exist when the current banking industry was being established.