Surveillance UAVs like Shahed-129 need no high speed.

That's their primary purpose.

Surveillance UAVs like Shahed-129 need no high speed. They take their 1,5-2 hours to get to the target area, then loiter there 'whole day', while observing from out to 40km away.

That's their primary purpose.

They're deployed as UCAVs - i.e. directly over the target - only if enemy air defences are not around.