It is pure marketing. I suspect that these companies know the low carb hysteria will come to an end and cash in now. It reminds me of dotcom IPOs.
One thing about the low carb fad is that it is making it easiier for diabetics to regulate their carb intake, both at home and especially while dining out.
Actually I know several companies have low carb products in the pipe line so I don't think that low carb is going away any time soon.
What will go away are the low carb that aren't. Yopleit yogurt, these drinks, some of the breads and all the stuff that is loaded with sugar alcohols.
I really hope that at some point they learn to make a decent sugar free ice cream.