As a developer this seems like a lot of extra work. I would assume that this was a supervisor’s idea.
But I wouldn’t necessarily consider giving the customer every possible option a bad choice. Giving customers the ability to fine tune their email notifications is really a bonus feature.
However, this is a horrible design choice to display 3 pages of multiple options. It’s an asshole design.
It would be pretty easy to group them into a drop down list where multiples in that category can be selected or deselected with a couple of toggles.
I would assume this was some genius executive decision, but there’s a very small chance it was a stupid design choice. Regardless the designer will always be blamed.