Because food and shelter in Vancouver is a lot more expensive than food and shelter in small town Saskatchewan.
The wealthier Vancouver population will pay more in taxes than they receive in UBI; UBI will be a (slight) drain on their economy.
The poorer Saskatchewan population will be receiving more in UBI than they pay in taxes. UBI will be a (slight) boon to their economy.
The less time he spends on the job, the better.