One more problem: Private Key either being compromised or stolen...
Similarity to Cash: None... We don't have anything backing cash except if it's in a Credit/Debit Card, or there may seem a possibility.
Solution: There doesn't seem a solution yet to me for BTC, as for the Credit/Debit Card, we can easily block it for the thief to become unable to use it...
compromised, stolen or lost.
You can lose your private key and be locked out from your own money forever.
I guess there is nothing similar with cash