The narration contrasts one faqīh with a thousand worshippers. It is not a formula for calculating the worth of every individual deed; the contrast highlights the protective and guiding influence of understanding.
أَشَدُّ is a comparative/superlative form. In عَلَى الشَّيْطَانِ, عَلَى is followed by a genitive noun.
Knowledge benefits people most when joined with sincere conduct. Using learning as an excuse to look down on others would contradict that aim.