It would be useful in the case of any payment that does not fit one of the existing types available  - Gift/Pledge, Pledge Payment, Split Transaction, Recurring Gift Schedule, Recurring Gift, Soft Credit or Disbursement.

I understand that allowing users to add custom journal entry types would be quite an undertaking, but I hope that a more generic title would not be too much work and still allow a bit of flexibility for those that need it.

In our particular case, we could use it for event and membership fees but this relatively simple change could be useful for all sorts of things for different users.