In Europe bank transfers are free and the standard way of transferring money. Cheques are pretty much extinct.
If American banks charge for them it's most likely because they can. It's standard practice in retail banking to offer commonly used things cheaply and then earn back the cost by charging loads for anything unusual.
As for how it actually works, in the European Bank I worked at we debited the account and then put the transfer in a batch file and sent it to the central bank which processed them every few hours. If the transaction failed for unknown reasons, someone would, I think manually review it.
If American banks charge for them it's most likely because they can. It's standard practice in retail banking to offer commonly used things cheaply and then earn back the cost by charging loads for anything unusual.
As for how it actually works, in the European Bank I worked at we debited the account and then put the transfer in a batch file and sent it to the central bank which processed them every few hours. If the transaction failed for unknown reasons, someone would, I think manually review it.