Because it’s cheap and easy to produce. Biofuels compete with food and forests. Not sure how much waste products can cover. Either way the biodiesel is about twice the price of the regular stuff here and has a lower tax rate than regular diesel (~43% tax rate)

It has a very high energy density. First Google result approx 10x that of batteries in EVs.

All the infrastructure is already built. EVs are becoming better and better options but the grid needs to be upgraded and the generation capacity increased.