I bought a few items in the summer sale the process was painful.
As it only allows you to buy one thing at a time the workflow was tedious.
Also, I had to manually remove bits from my favourites as I purchased them, this was a very unnecessary process.
Yes! It’s so aggravating! I want to purchase multiple items at at time but you can’t add them to the cart to just purchase all at once. And it makes you pay more taxes because you have to purchase individually!!! Like who thought this was a good idea? Has none of these folks been on steam? Steam will forever be the goat! I literally stop purchasing on EA because of the same issue. So archaic! It’s like do they not like money? Get with the times!! I wanted to buy from the sell got so aggravated and just went spend my coins on steam…lol… their lost 
This is the kind of feedback this forum is for! Excellent feedback.
I don’t work for Blizzard, but I agree that the Shop Website is really outdated in that it only allows one purchase at a time. There is no shopping cart for some unknown reasons. They only recently got the ability to use more than one payment type on a purchase…
Hopefully they do eventually upgrade to a website that allows multiple purchases in one transaction.