Paul's conversion is credible because it was Apostolically ratified and his gospel was identical to the Twelve's — Joseph Smith fails both tests

Key difference: Paul went to the Apostles and they ratified him (Galatians 2 — right hand of fellowship; Acts confirms multiple times). Peter explicitly calls Paul's writings Scripture (2 Peter 3:16). Paul's gospel was the same as the Twelve's gospel — identical core content. Joseph Smith has no Apostolic affirmation (impossible since the Apostles are gone) and teaches a demonstrably different gospel: different doctrine of God (polytheism / God was once a man), different Christology (Jesus as spirit-brother, not eternal God), different soteriology (theosis/becoming gods), different eschatology.