My embassy (EU-country) didn't provide a letter, in fact adamantly refused to provide one, saying the IOs had been warned and if difficulties occured I should tell them to call the embassy.
The visa agency called someone on the phone (probably a contact in Immigration), then told me "with [name of my country] ok without letter". The transfer indeed went through without a letter. It seems embassies have had their way.
Some embassies (eg Germany) will still provide a letter for a fee though.