vegan RDA triplot species arrows

Hi,

Why does vegan not plot species as arrows in plot? I know how to use
scores() and arrows() to create my own arrows, but it seems odd that
this feature is not built in. Is there ever a situation where species
*should* be plotted as points rather than arrows?

I checked ?plot.cca, vegan-decision, and google, but I didn't find
anything, (excepting the possibility of using biplot.rda, but only for
unconstrained analyses).

Thanks,

Tyler