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.
If you can store an email adress, you can store a payment adress. And also, you could do a transaction towards a forwarding adress that forwards again with not additional costs and problems and have everything sent to one wallet adress, if you wanted to.