Or, it self selects out people who would cost more money in support to the bank. If you’re in their time zone (and awake when they are), the bank could save money by only needing to have support available at certain times.

Similarly, they may not want to have you in their community. So, the community they form might be smaller, but more aligned with what they want.

They are definitely reducing their pool of customers, but maybe they are still attracting the customers they want. Why not let the market decide if they can find enough customers with this approach.

Honestly, the banks I use in the US often do something similar. It’s not as bad as this, and only on their online banking site, not their marketing site. They have maintenance windows late at night (in their time zone), and don’t allow logins during that time. It’s not always every night, but it’s often enough that I’ve noticed (at 3-4am).