If you play KF while in "steam-offline-mode", there is noch connection to the TWI-KF-Masterserver. This means your perks won't progress/be saved, so after you exit the game - all perk progress will be gone...
(There is a mutator, that let the listen/dedicaded server save the perk progress for the players, that play on that server. Don't know if this work with a "steam-offline-version" of KF, cause I don't know if you can connect to any internet-KF-server without authorisation of/by the TWI-KF-Masterserver?...
I although think, that you won't get any updates/patches/(FREE)contenupdates/DLCs (2 skin-packs available) for the KF-retail-version without an active steam-account.