In my humble opinion, an inline filter is absolutely necessary in our old trucks, and offers cheap insurance against costly repairs. Even though a carb rebuild kit isn't expensive, my time certainly is. And you can't put a price on loss of performance either. Only possible reason for not using one would be if you had a brand-new fuel tank and new fuel lines, and even then I would still have an in-line filter just to be on the safe side.
Just my two cents worth.