It makes sense to have a delay before locking the screen, so the user has an opportunity to easily get out of screensaver mode without having to enter their password if screensaver kicks in while they are in fact still actively using the screen. Ideally, the user should be able to shorten the delay, but it is defined as an integer of minutes.
In any case, the user always has the option to lock their screen with Ctrl+Alt+l before leaving it unattended. This is in fact the recommended practice. Leaving your screen unattended hoping it will go soon enough into screensaver mode is not recommended.
It makes sense to have a delay before locking the screen, so the user has an opportunity to easily get out of screensaver mode without having to enter their password if screensaver kicks in while they are in fact still actively using the screen. Ideally, the user should be able to shorten the delay, but it is defined as an integer of minutes.
You are correct, I didn't think of that. I've filed these feature requests:
In any case, the user always has the option to lock their screen with Ctrl+Alt+l before leaving it unattended.
Yeah, or just click on "Lock Screen" from the menu.
However, I filed this issue because Trisquel is more security focused than Ubuntu. And it's very easy to solve the issue by reconfigure the setting. But that is my opinion.
I too find it surprising that there is currently no option to set the delay right after the screen-locking checkbox, which will inevitably lead users to assume that there will be no delay whatsoever.
Maybe a simple hint in the UI would help (for instance: "Default delay before locking screen is 1 minute. This value can be modified in org.mate.screensaver.lock-delay in the dconf editor") so at least users would be informed about the existence of a delay.
Implementing the two feature requests you filed would be even better.