Sure it could be....but it most likely will not be.
STEEM is a specialized currency used on the steem blockchain which is meant to cater to the content creation community. The value in this blockchain is the curation reward system that we are employing.
STEEM is going to have a lot move value but it will not be money unless someone is operating on this ecosystem. There will be businesses build (they are already appearing) that will take STEEM for goods. However, stray outside this ecosystem and STEEM wont have much use except to exchange into another currency.
STEEM was not designed to be money even though it could serve that purpose in some capacity.