That’s not strictly true though is it.
What a butted spoke gives you is a reduced cross section at the mid point, so what you are describing is actually a “Weaker” structural element, if the same loads is applied over a reduced sectional area (per spoke) this means greater tensile stress on the mid point of a butted Vs PG spoke…
That slight reduction in cross section is intended to allow this of course so that the butted spoke is operating more in its elastic range (assuming materials and pre-load are the same), effectively the margin to failure is less, for a butted spoke…
Obviously the spoke is’t the only component under load in a wheel, it is of course under tension, butting is partly about tuning the component geometry to use more of the materials elastic properties.
Strictly speaking a PG spoke is stronger, it deflects less under a given load and requires a greater tensile load to cause permanent deformation, but this of course increases the chances of damage elsewhere in the wheel, like spoke holes or nipple threads…