Other than the optional try on appointment, what hoops have you needed to jump through?
I didn't have any. Just went to the store, tried it on and completed the order online there and then.
Personally, I hate ordering things online and will avoid it where possible. My preference is to shop in B&M stores where I can interact with an item before purchasing it with either cash or at a secure chip and PIN card paypoint.
Although it is not unheard of, it is certainly
somewhat rare for a customer to be told in a shop that the item on multiple display is not available in for purchase, not at any price or in any combination. Sure, your size in the jeans might be out of stock, or a certain issue of something might be on back-order, but when it comes to the Watch, not one is available for anyone in any shop. That's unusual, and it's off-putting.
I would not at all be willing to go through the order process on an iPad in a store. (Apple Pay is not available in my country, so I would have to put in my card details on an unsecured terminal over wifi, which I would not feel comfortable doing.)
If I were a casual customer (and I'm sure Apple has many of them, or this forum would be a lot bigger) and less interested in having an Apple Watch, I'd have just shrugged and gone to another shop.
I could be wrong, but I am willing to bet that for a lot of people "We have none available to buy today" is all they hear before their attention wanders.