I am sorry to say, but it not user friendly at all.
Keeping track of so many addresses can be a real pain especially if I am a successful shop with 10 - 100 transaction a day.
It seems that bitcoin is not suitable for large scale # of transactions.
How would you need to "keep track" of all the addresses? How do they give you more work? Addresses in bitcoin are very lightweight, and it's no problem to have thousands of them.
In retrospect calling them addresses was a bad idea, they should have been called "one time payment codes".