Could somebody explain, why Circle does not inherit the PlotStyle of the plot when used as PlotMarkers? Here is an example:

l1 = RandomInteger[100, {20, 2}]
cross = Graphics[{Line[{{-1, 1}, {1, -1}}], Line[{{1, 1}, {-1, -1}}]}];
circle = Graphics[Circle[{0, 0}, 1]];
ListPlot[l1, PlotStyle -> Thick, PlotMarkers -> {cross, .03}]
ListPlot[l1, PlotStyle -> Thick, PlotMarkers -> {circle, .03}]

This seem to work as expected, but the only difference is that Graphics is given a list of primitives:

circle1 = Graphics[{Circle[{0, 0}, 1]}];
ListPlot[l1, PlotStyle -> Thick, PlotMarkers -> {circle1, .03}]