Danny, if there is a way for the fee to be added, via the technology, so that when I send the BTC I cannot choose to not add the fee, then I will be happy to stand corrected.
Read about:
"Child-pays-for-parent"
and
"replace-by-fee"
with Blockchain.info unconfirmed transactions get cancelled after 24 hours.
This is not true. It is not possible to "cancel" a transaction after you send it. You can stop broadcasting it and hope that all the existing peers will drop it from their memory pools, but the receiver can continue to re-broadcast it forever without your permission.
Zero confirmations is definitely not instant under these circumstances. Zero confirmations simply means that the transaction may go through, and with no miner's fee paid there is a good chance it won't.
This doesn't sound any different than a credit card or PayPal transaction?
Bitcoin is still in its infancy. There is SO MUCH more development and innovation that will come in the future.
You are basing your opinion on the only ways you are aware of currently to make bitcoin based transactions. I think if you come back here and re-read your thoughts in 10 years, you will be surprised and perhaps feel a bit foolish.
Imagine internet users in the early days (when TCP/IP was less than 5 years old) trying to picture what the internet would be like today.