I'm not sure what the article claims here. This is the first dated inscription but the positional arabic notation (with a zero like glyph) had been in use for at least 300 years earlier. If you consider other place value systems the concept of a 'separator' goes back much farther.
This isn't necessarily evidence that they understood zero as a number as opposed to a concept. By 1000 in Europe they used a symbol as a placeholder that looked superficially similar to our modern glyph of zero. When explaining it, however, it was clear it was simply a placeholder that could always be omitted and was "sometimes useful" and was absolutely not really a number. It isn't clear that the glyph used here or in Europe was anything more than an elaborate 'dot.' It certainly didn't seem to be be transmitted as a recognizable glpyh but each culture rendered it in the way most convenient as a counting and placeholder aid.
Yeah;all this talk of 'placeholders' that don't matter. Every digit is a 'placeholder', standing in for the count that it represents. Not convinced.
If it was used in a power-of-ten (or power-of-anything for that matter) for 'nothing here' then it was a digit, it was zero, and it should be considered a legitimate heir to our zero.
This isn't necessarily evidence that they understood zero as a number as opposed to a concept. By 1000 in Europe they used a symbol as a placeholder that looked superficially similar to our modern glyph of zero. When explaining it, however, it was clear it was simply a placeholder that could always be omitted and was "sometimes useful" and was absolutely not really a number. It isn't clear that the glyph used here or in Europe was anything more than an elaborate 'dot.' It certainly didn't seem to be be transmitted as a recognizable glpyh but each culture rendered it in the way most convenient as a counting and placeholder aid.