If my teeth are not properly aligned, are there health reasons aside from wearing down my teeth for getting braces?

Depends: Improper alignment of your teeth can be cause many different and real concerns -even airway obstruction. It is hard to tell from your questions how this affects you. If you are not sure of the recommendation made by your orthodontist, consider a second opinion and take your time. Getting braces is rarely an urgent issue :).

Malocclusion: Poor aligment can lead to grinding (bruxism) and TMJ disorder which is very painful!

Absolutely: Worn teeth may require extensive and expensive restorations that have to be periodically redone. Crooked teeth and bad bite can result in damage to the bone/gum tissue around the teeth and/or damage to the temporo-mandibular (jaw) joint, requiring extensive and expensive treatment. If they don't look right they are not working right. Please see an orthodontist for individualized assessment.

Many: When the teeth are crooked or misaligned, it is harder to keep them clean. This often results in a greater chance of cavities and gum disease. To a lesser extent there is also a greater chance of muscle and joint pain.