I think Rand using the TP was an unpredictable side-effect of his balefire link to Moridin and thus something the DO, as the uber-control freak - certainly wouldn't want. Using the TP once doesn't make you addicted. In the end, the TP usage just allowed that Rand could free himself before Min's death and instead kill Semirhage. Without using the TP, the Shadow had most likely won. But we will see!