If anything, the reverse is a security risk: applications that steal focus while I am typing down a password.
Windows and macOS pop up the default browser (or on macOS, a webview) with the captive portal when they detect one. iOS doesn't have windows, so if it wants to get the user to do the captive portal without them sitting there in confusion it has to pop it up. It could pop a notification, but if the user misses it (as one could, with all the notifications that come in these days), then they are stuck.
0: https://support.apple.com/en-us/HT205296 (which has kicked in for me sometimes when my LAN doesn't have internet for whatever reason)
The current situation is incredibly badly-engineered on so many levels. It’s maddening, really. One of the worst parts is that the modal disappears as soon as you attempt to switch apps (or god forbid you try to respond to a message you received)
Notification + real internet connectivity indicator + a regular Captive Portal/Internet App would go a long way.
It does, they're just normally fullscreen ones.
The point is that that captive portal windows persist in the app switcher, and they can't be splitscreened on an iPad. So if you need to look at your email or text messsages to find your user credentials or the login page is badly coded and doesn't pick up your password manager you're screwed. It's really, really annoying.