Rally points let you set a map location where all units produced from that town will be sent. This can be a valuable function but it has a number of bugs in it that can really screw up your game included "The magical mystery tour" bug where units head off to God knows where plus interference between the pathfinder algorithm and changes in road networks or temporary path blockages by brain dead allie units just passing through.
The auto bombard function is particularly disturbing because it has several bugs built in that include: 1) bombarding when there is nothing that you can possibly hit, 2) coming off of the bombard task whenever an enemy unit approaches (example: you have 20 artillery next to a city in a stack defended by three mech infantry. If the AI sends a longbowman out of the city to attack the stack "Ooh scary!!" then all the artillery will stop bombarding and sit there as if they were in a coma.
Auto bombard is also particulalry wasteful because you want to bombard towns to expose and destroy units where you have a strategic attack advantage. When a 1 defense unit like a longbow gets expose, you want to attack it and kill it instead of just bombarding it down until it is weak enough to hide behind a wounded 6 defense rifleman.
Autobombard will also target improvements that cannot possibly be destroyed so you get goofy messages like "barracks destroyed" in a town that belongs to a civ that has Sun Tzu's in another major city.
For naval units, autobombard wastes significant resource against stationary targets and does not work against mobile targets.
This is one of those buttons you would rather have your money back on.
