Is having thin veins good, bad, or neutral for health?
Having thin veins is not at all good. Rather it's a sign of abnormality.
A person having thin veins can never remain as healthier as a person having normal veins.
The reason for this is that veins provide the path for blood flow to different organs of the body, and if the blood can't flow at normal rate then it definitely would not spare body to function normally without specific cures and treatments.