yes you're right, this can be a tricky way to avoid bad SLA.
but anyway, this is something that is truely needed. Lot of times, we need more information / feedback from customer for better diagnosis, and waiting for him, we cannot let the sla running !
Other situation is when we have thrid provider, and then, we cannot let the SLA running wither when we are waiting for third provider.
Badly used, pending status is useless, you are right, but anyway, this is something truely needed for at least the 2 reasons I gave I hope that developper will / have already understand that