Less efficient? Dunno why they're even trying now. Don't see many people buying one, at least the S7LN had a few buyers. If they did something like the LN with the S9 I'd buy it but just looks like the one fan variant of the S7 they did a while back.
Assuming they needed to use low quality ASIC's somehow. Easy to overvolt and this is their answer. Are they using them in their new data mining centre? doubt it, unless they are for investors sections of the mining center.