Latex paint uses water and synthetic polymers as its base, so brushes and spills clean up with soap and water. It dries quickly, resists fading, and so it has been made the standard for interior walls and most exterior work in Denver.
The “latex” name is a leftover from when rubber-based binders were common; today the binders are acrylic or vinyl polymers. What matters in practice is the performance: fast recoats, low odor, and flexibility that handles the expansion and contraction of a Denver exterior subject to ever-changing climate conditions.