Unfortunately for many roof contractors out there, or more specific the man installing the roof, it’s more important to get the roof complete quickly than properly.
The outside cladding (siding) is the first line of defense to shed a windblown rain and allowing the house wrap to shed only the splash- in water at the overlaps, not free flowing water from improper flashing.
Millions of dollars worth of damage are done to buildings due to stucco failures each year. Don't let this happen to you.