I see what you mean.

It looks like in the first picture the rider has room to raise the saddle a good bit without it interfering with her body position. Maybe not though. Hard to tell from a picture. Whatever makes the rider feel comfortable and balanced is the right height, for sure!

For some examples for terrain I'm working with here in central Texas, we have a lot of short but steep downs and ups. I ride this without dropping my seat:





This is one I'll drop the seat for: