Or, more to the point, suppose someone came with a different system of units and said: look, one of our standard lengths is 10^-6 of one of yours, but one of our standard areas is defined just like yours: 1 ha = (100m)^2 and (1 of our areas) = (100 of our lengths)^2.

In other words, their standard length = 10^-6m; their area = 10^-12 ha = 10^-8 m^2.

Is their standard area bigger or smaller than their standard length?

Notice that in proportion the lengths and areas are the same.