I'm going to have to disagree with this. You can catch people daydreaming and not paying attention to objectives all the time. Stealth is great in PvP!
Its not bad in open world pvp. I've been on the receiving end of stealthed enemies even when I was aware that they could be around....and I've snuck up on the other side too with ease. One time there was an opposite faction player I could tell was actively looking for me and I managed to sneak up behind him three freaking times and kill him. (I killed him once in an attack of opportunity and he returned to the area twice for payback. We were equal level, too)