Overall I'd say it's a fine 4th or 5th perk if you regularly play with friends and have a tank that is good at doing module damage. Compared to a skill like Camo or Recon that is always in effect it's simply not as good to have as those as they render a permanent benefit. That said, it's usefulness is limited by the fact that is is a situational perk it's completely useless if the enemy tank has taken no module damage. The perk definitely had tactical advantages when it worked, especially when synergised with communication and teamwork.

Or, if I knew an enemy tanks engine/turret traverse was damaged, I could inform my platoon mates in faster and more agile tanks so that they knew circling said enemy would be safer. For example, if I could see that an opposing T-150 had a damaged ammo-rack I could snap off a few more shots at him before retreating into cover than I normally could.

Tactically it was actually fairly useful to see the damage tanks had sustained. I took the perk out of curiosity as I thought it would be cool to see the effects of the KV-2s derpy HE goodness in terms of module damage to tanks, and similarly my gunner had Deadeye so in the Churchill III, with it's amazing rate of fire, I could shred modules/crew and wanted to see the effect there as well. I've used it before on my Russian heavy crew because, at the time, they were the crew for my Churchill III and KV-2.

Eagle eye guns