bitcoin is harder to insure because guaranteeing the safety of keys remains a challenge.
If I steal your keys, I steal your Bitcoin. And it’s easier to steal the private keys to $40M in Bitcoin than it is to steal $40M in gold (700 kg).
What I meant with my poor analogy is that if a bank is planning on blocking customers from withdrawing funds, it’s much harder to ship out the gold to their friends than to ship out Bitcoin. It’s pretty trivial to allow Bitcoin withdrawals. It’s just logistically hard to coordinate the transport of 700kg of gold out of the bank and to somewhere else.
arguably, if we are making value statements, there are a set of similar trade-offs for physical protection of keys vs. primary material. 700kg is harder to move: that's a security feature. keys are small: that's a security feature, because they are a small O(1) surface area to protect regardless of how much value they maintain control over at any given moment.
these are simply tradeoffs. it is only "easier" to steal keys if they are left unprotected.
here's the enormous truck you would need to carry $40m in gold, apparently: https://www.tkingauto.com/mini-truck/rear-single-tire-truck/...
It can lift it several stories up, into the building, where the bank can unload it safely without risk of robbery.
Also, of course, you can't actually steal bitcoin, you can merely steal the keys. That is an actual distinction because possession of the article itself is meaningless without the other half of the cryptographic operation it takes to move it.