Assuming you are referring to in-home garbage disposals:
The pros of having a garbage disposal are that they can save you time and energy when dealing with your kitchen waste. Instead of having to take your waste out to the curb or compost pile, you can simply turn on the disposal and let it do its job. They can also help to keep your kitchen cleaner by preventing food waste from sitting in the sink and attracting pests.
The cons of having a garbage disposal are that they can add to your water bill (since they require water to operate) and they can also cause plumbing issues if not used correctly. If you put things like grease or coffee grounds down the disposal, it can cause clogs in your drains. It's important to be aware of what you can and cannot put down a garbage disposal to avoid problems.