Well - you do have to use an intermediary to exchange bitcoin for fiat, that is correct. I think the vision is that one day fiat will go away and be replaced by bitcoin and other cryptos though.
Everything is quite clunky right now, and not exactly easy but that is true of any new technology.
Yeah, that's why you use escrow, or an intermediary service. By the way, I never claimed you should use cash.
In fact, most of the criticism I have towards Bitcoin also applies to cash, as you've sarcastically pointed out.
This is one of the growing pains of bitcoin that will have to be worked out. You can send bitcoin to addresses that nobody holds the private keys to and those coins will be gone forever. There are likely already several hundred thousand or millions of bitcoin lost this way.
There is no reversal of a transaction, the ledger is immutable.
With all of that said, bitcoin was not created to solve crime.
There's still intermediaries involved and they're not exactly simple to use.