Do I want to know more, in the transaction process if the error then the bitcoin is lost?
I think that will be depend on the error, if it's error cause wrong bitcoin address, it will be lost forever and if it error because wrong address format, transaction wouldn't be executed and the fund will be refund to the sender address.
With the wrong address format, the funds will not be "refunded" to you in any way since the "Send" button will not even function. Your bitcoins will not be moved as there were no transaction that has taken place in the first place.
Do I want to know more, in the transaction process if the error then the bitcoin is lost?
The only "error" that you should be getting is none other than "Invalid address format." or "Insufficient funds." Both errors will not make you lose your bitcoins as the transaction will not come through. Once there's a valid address, sufficient amount of bitcoins to cover the transaction, then the bitcoin will be sent to the address. Sometimes it takes more time than the usual. There are traffics in bitcoin transaction as well but it's appearing a lot less than before even with small fees.
Why would be Bitcoin Transactions Re-Fundable???!!! do you get a refund when you invest or spend fiat?
Obviously not when the transaction is done with physical money. In order for refund to take place in that, you have to convince the seller that you are reasonable to receive a refund. Otherwise, you can't just get refunded in buying things. On the other hand, in another part of the digital currency world, Paypal (the company), you can issue a dispute there. The thing with the dispute function is that it's abused by scammers and they have 180 days to dispute a transaction. A surefire way for them to get their money back is to claim that they got hacked and they didn't authorize the transaction.
I wonder what would be of bitcoin if we had that function. Would it be the same? I think the crypto world will be filled by scammers, just like the world of Paypal, and there will come a cryptocurrency that will overthrow bitcoin's from its throne simply because it has no dispute function. Dispute function is simply a flaw that people can easily abuse.