The system is not identical to that of the USA. However, in regards to updating the credit file, the inquiries are updated almost instantly in the USA as well. People often misunderstand the purpose of an A-O-R or 2/3/4bm. If you are not applying for multiple cards from the same bank, the only advantage is "good housekeeping". Although no one knows for certain how it all works, there have been claims that doing them at the exact same time from multiple browsers will increase odds of instant approval, there have been many claims against that as well. I can only confirm first hand about the Canadian system.

For example, if you were to apply for 2 cards in one day (Amex and then CIBC) and then a TD card afterward, TD will certainly see your 2 inquiries, as did CIBC after you applied for Amex. They won't know whether you were approved/declined but they will see the pulls just the same as if you were to apply the next day or the next week. However, applying for multiple cards within the same day may have benefit. I cannot confirm but in the US if you apply for multiple Amex cards within the same day it will produce only 1 HP, so there is one purpose of doing applications in the same day. The same works with BofA for the Alaska Airlines card. Perhaps MBNA would act the same way. Credit card companies are more aware than you may have thought.