Also, when you say the +0.01 and +0.70 there, aren't you implicitly borrowing anyway? It's just "easier" borrowing -- you say that 0.09 + 0.01 = 0.10, as opposed to explicitly borrowing the 1 to the second decimal and subtracting the 9. Similarly, you say that 0.30 + 0.70 = 1.00 instead of borrowing the 1 to the first decimal.
I can see why this makes mental maths easier, but I don't see that it is any deep conceptual improvement over the borrowing. Is one of the goals of Common Core to improve mental arithmetic? If so, then this makes sense. Otherwise, unless you properly explain why the two are equivalent, and why the other method is faster, it's more like a neat sleight-of-hand trick that might leave kids slightly more confused about why it is "better" than the borrowing method.
[Reference: Non-American, non-parent who knows very little about the American education system, but has some friends teaching in it.]