If you pull down notification bar before unlocking the phone and hit the settings button. Takes you to settings and you can back out to an unlocked phone.
I just tried it and you are right. It doesn't really matter since it isn't a secure lock or truly locked like if you were using face, pin, or pattern to unlock.
Question isn't it easier just to slide unlock rather than to pull down the notification bar, go into settings and then back out to the homescreen? lol
Remember that "unlocking" the phone via the slider is just a way to prevent unintended app selections or keypresses in case the power button is accidentally pressed. If you haven't selected a security method like face, pattern or PIN unlock, then your phone isn't secure, and anyone could use it.