These Doubloons costs look correct. There are three tracks:
Free Track - Freely Available Rewards
2500 Doubloons - Additional Rewards as you would expect for spending Doubloons
6250 Doubloons - Additional QoL Benefits/Bonuses
The largest version provides some benefits which can be seen in the above photo. The "Battle Pass Missions: 1" references an additional mission that a player can complete to get Battlepass progress. It's not needed for completion of the reward track, but it can help players who'se game interaction is more sporadic.