For me it has to do with starting points.
And if the supplied library doesn't show a good range,
I'm liable to not use the synth that 'came free with the DAW'.
Most of what was supplied was noise, some made even worse by the clipping.
Seems like there were around five patches that were okay starting points to edit from.
I'm sure there's a market for those other noises, but not for my music styles.
With so many synths competing, I'm going to go with the one with a usable library.
I used to do the full on programming from scratch,
but that seems counter productive to me now as it's just faster to find
something close and edit it from there, so I can get back to recording it.
I found the Xenos library gives more and better 'starting' points for Z3ta
(and they're quite cheap too.)
But buy them direct from Xenos and not from the Cakewalk Store
as Xenos sells them for half the price ($5.25 vs. Cakewalk's $9.95)