Season Challenges - benefit of gold pass?
When you click on the plus icon on bottom left; a screen opens with tabs Challenges, Rewards and Perks. If you go to Rewards; it shows Rewards you will earn as you complete challenges. Bottom line is by default and rewards shown on top line are available ONLY to people who have gold pass. So, people with gold pass get both rewards of bottom and top line.
I will recommend you to go for gold pass; because for 5 USD; you will get so many rewards in a month. If you would want to buy them normally they would cost significantly more; might be 500 USD.