The original SFSafariViewController did share cookies with regular Safari. The documentation says
> In iOS 9 and 10, it shares cookies and other website data with Safari.
I was also also disappointed that they removed it in iOS 11. But it's still a step-up from other even more horrible in-app browsers like in Instagram, which are implemented with WKWebView. I refuse to read anything in those in-app browsers; I always manually open them in Safari.
lol what you’re describing as a ‘feature’ is actually insecure & vulnerable. There are strong security reasons why Apple mandates WKWebView and bans SFSafari.
SFSafariViewController is not banned. It's recommended by Apple for some use cases. It says,
> If your app lets users view websites from anywhere on the Internet, use the SFSafariViewController class. If your app customizes, interacts with, or controls the display of web content, use the WKWebView class.
> In iOS 9 and 10, it shares cookies and other website data with Safari.
I was also also disappointed that they removed it in iOS 11. But it's still a step-up from other even more horrible in-app browsers like in Instagram, which are implemented with WKWebView. I refuse to read anything in those in-app browsers; I always manually open them in Safari.