If you are losing pints of blood, you would need resus and quickly!
Direct pressure and elevation would stop most bleeding. And a dressing should not be judged by the amout of blood which is absorbed, although in the ER if I see a completely soaked TrauMedic dressing, I could guess the casualty would have lost more than a pint of blood.
A dressing should be to:(as you rightly said)
1. Apply pressure to a wound to reduce/stop bleeding.
2. Protect the wound from further injury/damage/exposure.
3. Blood clotted in the dressing would enchace the clotting mechanism to ensure that the bleeding is arrested, assuming of course the casualty doesn't go into shock 1st though.