Level based access

I found it interesting the other day that I have, as a level 8 rider, access to Alp Du Zwift which I believe requires level 12! I am, however, a level 13 runner. So it appears that some things in Zwift are linked to Riding level and other things appear to be just Level in general. Is this by design or a bug and if by design how do we know which level actually applies to various access to features/functions/‘gifts’ etc?