Nicotine helps prevent Alzheimers and Parkinsons (and something else that I forget). Nicotine patches are sometimes prescribed to people who are at high risk of those conditions in the UK.

Nicotine works as a stimulant. Helps you focus your attention and remember stuff better. Similar to caffine.

Sometimes... People might crave nicotine because they are self-medicating. Smoking is terrible for you (because of cancers and the like) whereas nicotine... Might be... Fairly good for you at low doses...

If you chew gum then do you get a hit from chewing? It might be that psychologically you chew instead of smoking.

Patches are more constant (no hit if used as directed). Maybe... Move to the patches and gradually taper down from those if you really want to quit nicotine?