Vector, I think you're missing the point. The lower NRR of electronic muffs is because they are a compromise. When paired with plugs underneath, electronic muffs are very safe to use, and amplify low level noises enough to hear through the plugs. This is important for hearing commands from a Range Safety Officer, hearing commands or corrections from an instructor, or just being able to talk to your buddies without taking your ear pro off. If you look at the cups on a lot of the electronic muffs, they are slimmer than regular muffs, and may have scalloped sections to provide a better cheek weld, or fit under a ballistic helmet. The slim cups can't possibly provide the NRR of a huge cup full of foam, but they're a lot easier to shoot with and wear all day.
So you're right. If your only concern is getting the highest NRR available, electronic muffs probably aren't for you. But, if you have to wear your ear pro for prolonged periods, and be able to communicate with the outside world without taking your ear pro off, they are worth a look.
