Just some testing with Spotlight mechanics, apparently we can target any opponent's pokemon however they never seem to attack their own allies making this move very situational.
I thought this had already been tested but it's not in the OP. Hm.
I think the move more for battle Royales. But there are some niche strategies that can be used eg Spotlight+King's/Spiky Shield, or two Pokemon with Spotlight/Protect could Stall.