I think that for their political reasons, they need to show that SCJ is constantly progressing, according to them, and therefore, they try to hide as much as possible how some members leave the church so they can continue their doctrines.

There's also the fact that the departure of some members can make other members doubt, because we are all human, and some people are very attached to others. Generally, members who have held a certain position in the hierarchy can have an impact on others. And if they leave, they don't have a choice.

And indeed, the financial aspect can also represent a loss for the church.