I think toe blending may affect Fatigue life:

Toe
Boundary between a weld face and the parent metal or between runs. This
is a very important feature of a weld since toes are points of high stress
concentration and often are initiation points for different types of cracks (eg
fatigue and cold cracks).

And

Due to the smooth blending between the weld face and the surrounding parent
material, the stress concentration effect at the toes of the weld is reduced
compared with the previous type. This is why this type of weld is highly desired
in applications subjected to cyclic loads where fatigue phenomena might be a
major cause for failure.
Figure 2.31