Not always. You get more valve open time:lift but you have to deal with the rollers. I've done serveral gen 4 V8's with lifter skid issues from low roller speeds. Roller cams were a race thing until people figured out they could alleviate roller skate (I know) with point pressure. The issue is worn engines struggle to keep the rollers from skating. Flat tappets are far less prone to failure if the first 20 mins of life is sucsessful. Even if you flatten a lobe on a flat cam all the gaskets arr fresh and reusable.
