Any benefit would only affect the components in contact with the liquid fuel.
Your fuel pump might have less rapid metal to metal wear on fuel wetted friction areas.
Other characteristics of the biodiesel blend might have detrimental effect.
Biodiesel is hygroscopic, water in the fuel won't settle out and you may have more rust or corrosion.
Residual methanol in the fuel might hasten the breakdown of the synthetic 'rubber' seals.
In all honesty, the increase in longevity, or hastened demise, would be hard to tell from a reference base line of a car that ran only ULSD. Maybe with 50 cars, 25 on ULSD, and 25 on B5 (or B20), a statistically significant difference can be detected, but one car? One that has already been in use and wearing? You'll honestly never 'know'. A fuel system failure could be attributed equally to either ULSD or to a ULSD+bio blend, and no reasonable counter argument would be logical.