Nokia 8 Sirocco and Nokia 7.1 are different from the other Nokia phones which could be unlocked by a unlock key. These phones do not support the old method. So, to unlock these phones, we need to modify the internal partition to gain the unlock ability.
You can use the phone normally after the unlock. You can root it and also flash GSIs. Also, Nokia 8 Sirocco source code is now available, so there are chances for some amount of development.