[therein]

KW per hashrate doesn't make much sense. At that point you're just comparing the efficiency for the available hardware for hashing function, ASICs that are designed to handle up to calculating SHA256 of up to 1MB of data versus scrypt ASICs.

Since that's the case, your statement of "of the very popular older coins only XRP is more efficient" falls apart as at the very least Litecoin would need to be at the exact same spot.

And if you are talking about per mined blocks, then you are putting the network difficulty into the picture and arguing a lower network difficulty (hence lower network hashrate) as a selling point isn't going to get you anywhere.