Note: This post in mainly meant to inform and hopefully get Coinbase to resolve this issue. I've exchanged emails with Coinbase support and while they were nice, they didn't resolve the issue and instead ignored it/placed resources elsewhere.
The issue at hand: On iOS 10 your invoice isn't properly prompting to open the user's default wallet when pressing on the QR code. Please see this screenshot: http://i.imgur.com/jN1DoLc.jpg
When the user taps "Open", nothing happens. When it comes to BitPay's invoices, they are handling the call to action correctly – the user is able to open their default wallet as it says "Open 'bread" (in my case, breadwallet is my default wallet on my phone)
In the case of the BitPay invoice, all the payment information is filled out when my wallet opens. I just confirm and pay, super easy. With Coinbase invoices I have to copy my Bitcoin address, paste it in my wallet, type in MANUALLY the amount of Bitcoin to send. It's a pain, please address this ASAP.
By having these issues, you're making paying with Bitcoin on iOS 10 painfully unnecessary. Nobody will use Bitcoin as a payment method on mobile if you don't address issues like this.
One last thing: your Mobile invoices (for users that don't use Coinbase wallets) don't have any information on HOW to pay. How on earth are people supposed to know that you are supposed to Hold down on the QR code to begin the process of paying (aka prompting the wallet to open)? It's incredibly confusing and nobody outside of enthusiasts are going to understand this.
At least with BitPay their invoice has a prompt that says "Open Wallet" which prompts (correctly) the opening of the wallet. The Coinbase invoices were NOT having this issue on iOS 9 and earlier, they worked properly. This is an issue that has been ongoing since the iOS 10 release, which was in the middle of this past June.
You guys are a good company with strengths but you need to address this issue amongst others.
Thank you for reading.