Wi-Fi networks that use Captive portals (like a Sign In page) can be a real headache. You connect to them, and then try to figure out why nothing is loading, and finally Android shows the 'Sign in to network' popup. Starting with Android O, the Settings app makes it more obvious that you are connected to a public Wi-Fi network.

Left: Android 7.1.2 (LineageOS ROM); Right: Android 8.0

While the 'Sign in to network' notification hasn't changed at all with Android O, the Wi-Fi section of the Settings now has a large button to login when viewing a Captive portal network. In earlier versions of Android, the network info shows 'Sign in to network' as the status, but tapping on it doesn't do anything.

Not a huge change by any means, but definitely helpful when you're trying to figure out why the Wi-Fi isn't working. On a similar note, the new network info screen is much nicer.