yeah u would have to logon and make a new char, since single player characters arent portable with battlenet realms. the advantages are that there is no hacking or cheating of any kind int he realm games, not only is it not possible, its illegal because the users would havet to hackt he blizzard servers.
the disadvantages are that there is lag, and at this ti me of night, A WHOLE lot of lag. if u do make a char on the realms, make it on US east.]