I can't speak for Apple, but they do note in their support document about hidden networks......https://support.apple.com/en-us/HT202068.......that "Hiding your network doesn't secure your wireless network, because the SSID (name of the network) can be discovered in other ways."
There are any number of free and inexpensive utilities available on the Internet that will reveal a "hidden network" in seconds, so anyone who wants to look for and find a "hidden" network around them will have no trouble doing so.
Fact is, a "hidden network" is not really "hidden" at all if you are using iOS or Mac OS. The SSID (name of the network) is always being broadcast at all times on iOS and Mac OS.
iOS and macOS always connect to known networks, hidden or not. The fact that iOS 10 might warn about this.....(I can't find a specific document from Apple about iOS 10, so maybe you could help out here)...... would indicate to me that Apple likely has no plans to add the kind of toggle switch that Microsoft added in Windows 7, or to force the user to connect manually. Therefore, iOS and macOS constantly broadcast all the hidden SSIDs they are capable of connecting to.
I suppose there is no harm in trying to "hide" your network if all of your devices can connect without difficulty......(some iOS devices do have problems trying to connect to some "hidden" networks)......but it certainly won't stop anyone who wants to see any "hidden" networks in close proximity.
Bottom line......hackers laugh when they encounter a "hidden" network, so be sure to use WPA2 Personal security and good strong password for your network. If you are really concerned about the security of your network, change the password once a month or so as well.