Are you referring to where the opponent uses Torrential and you use Starlight Road, or where you use Torrential and then Starlight Road?
In the first case, it's obviously good since it's a +1. In the 2nd case, it's more of a desperate play, since it's a -1 in card advantedge, but you get a Stardust that can hopefully turn things around. If you're opponent isn't activate any cards that can trigger Starlight Road, then sometimes, the only option is to activate it yourself by using your own cards. I've done something similar before, although I activated Heavy Storm and then chained my own Starlight Road because I was in a situation where that was all I could do.