For those who are diamond, which is likely most of this board, I can see this change has being helpful in a few ways.
I often book my reward tickets at two one-way flights, booking the outbound when availability is first released, and the return later. With only a $30 cancellation fee, it makes it easier to book a few different outbound options on successive dates, increasing the odds that return seats will come available for the desired trip length, and then cancel the outbound options not needed.