I believe the ezselection datatype stores just the NUMBER of your selection. In other words, 0 if you select the first option on the admin side, 1 if you select the second, and so on.
From some code of mine, in which I used a selection datatype to record the specific image alias I wanted to apply in a given case:
As you can see, since it's a SINGLE selection, we access the value by referencing the 0 element in the array. If it were a multiple selection, there might be more elements in the array.