"There is no point in selling if you are not going to be paid and the only reason that the bank's collection services are needed because the exporter does not trust the foreign importer..."

If trust exists, there is no need to
use and pay for the bank's services.

There would be instead the same payment terms as adopted by most commercial transactions within a country - whereby one firm sells goods to another, sends them the invoice, and in due course receive payment...

...This type of payment
arrangement is known as open account.

Confirmed versus Unconfirmed Irrevocable letter of credit from a bank, is still not a cast-iron guarantee of payment. Not every foreign bank is scrupulous or financially solvent.

Sometimes a foreign bank, for one reason or another, will not honor its own financial commitment or perhaps due to, the sudden imposition or alteration of foreign exchange controls in the importing country may make payment impossible, even though the foreign bank wishes to honor its commitment.

A confirmed, irrevocable letter of credit, means that the exporter's bank undertakes to pay the importer, should the foreign bank fail to do so. 

The exporter's bank may be reluctant to confirm a letter of credit if it has any doubt as to the trustworthiness of the foreign bank.
See Trade Consignment

If the sales agreement between the exporter and the foreign importer has stipulated payment by sight draft (i.e., no credit), the bank in the foreign country will ask the importer to accept the draft and pay the amount indicated.