Even if there is already an article about this issue, I want to bring another usage of these operations into your mind:
While doing maintenance, we are used BACKUP LOG WITH TRUNCATE_ONLY to truncate the transaction log. After the maintenance, we inform the user that a full backup must be performed to restore the normal backup operation chain. Even if the this is not immediately done, the problem will be automatically fixed after the next (scheduled) full backup.
This is now not possible anymore! Why is it so bad to have a command like this? If the user/sysadmin/developer knows what (s)he is doing, there is no problem with this command.
As a workaround, I now have to switch to the simple recovery model during maintenance. But if our maintenance application crashes, the database will stay in the simple recovery mode. Therefore the workaround is causing a higher chance of data loss, exactly the opposite of the intention to remove it. Somebody must now manually set the recovery model back to full!
Please consider bringing this helpful option of the backup command back.