=?UTF-8?Q?Re=3A_=5Bxml=2Ddev=5D_Don=E2=80=99t_create_elements_with_simple_co?==?UTF-8?Q?ntent_and_attributes?=
So if you claim as you have that
<Cost>
<Currency>USD</Currency>
<Amount>8.95</Amount>
</Cost>
is explicitly labelled
then let's look at a plausible extension of that.
<Cost>
<Currency>USD</Currency>
<Amount>8.95</Amount>
<Currency>GBP</Currency>
<Amount>6.95</Amount>
</Cost>
Here the relationship between the Amounts and the currency that applies to (labels) them is the immediate preceding sibling.
But that relationship is not explicit. It's implicit. So your designation of what is an explicit label is neither coherent nor rigorous and therefore not an appropriate arbiter for determining what is good or bad.