Perhaps I'm mis-understanding the question but when could we ever purchase gold/crowns to start with? As far as I saw looking at steam the other day you could only purchase some of the content that is already available for sale at the ESO store.
If the question is referring to using in game crowns to purchase anything outside of the game at the steam store, I would think this possibility will be unlikely. ESO gains nothing by doing this in my opinion.
Edited by thesilverball_ESO on February 11, 2015 7:23PM
If it functions like similar games, we may see a "starter pack" bundle sold on steam and the rest will be handled in-game through the crown store. Not sure if they'll do a link up with steam to use the steam wallet when purchasing in game. As of right now we have almost no info how this will work. We will probably get more answers nearer to the March 17 switchover date but beyond that it will all be speculation.
"It is a time of strife and unrest. Armies of revenants and dark spirits manifest in every corner of Tamriel. Winters grow colder and crops fail. Mystics are plagued by nightmares and portents of doom."