There are two reasons:
To comply with Anti-money laundering regulations - We perform due diligence checks on the source of wealth of our customers to prevent financial crime.
For the protection of our players - Knowing information about your income and wealth helps us provide a more responsible service. As part of a source of wealth check, we’ll try to understand what level of activity you’re personally comfortable with, taking your income and other available funds into consideration. We would never wish for you to gamble more than you intended.