The golden rule of thumb is always: "not your keys, not your coins". By storing your Nano on an exchange, your funds are pooled together into one or more giant wallets. This is risky for several reasons (keep reading). By withdrawing your funds from an exchange you are helping yourself keep your funds safe, as well as helping Nano become more decentralized.

Avoid stolen, frozen or lost funds

Keeping Nano on your favorite exchange is conveinent and inexpensive, until something goes wrong. While reputable exchanges (Binance included!) may have low risk, there is always the chance that an exchange gets hacked, and your funds stolen. Sometimes the exchange is perfectly secure but may incur in some financial or legal problems, due to the "gray" legal area that is crypto in many countries. This might result in your funds being lost or frozen indefinitely. Even if the exchange is completely safe, your account may still get frozen. For example, an exchange may freeze your funds because someone tried to force into your account. Always remember: if your Nano are on an exchange, you don't fully own them. The beauty of a decentralized currency is that nobody should have control of your funds, except you!

Make the network more decentralized and secure

Another major reason to own your Nano is to help the network. Due to the way the Nano protocol works (and many other decentralized currencies), if too much of the available supply is controlled by a single party, it decreases the security of the network. Currently, the majority owner is Binance, which controls approximately 19% of the total supply. Not only does this make a majority attack easier (if Binance were to get hacked), but it enables traders on Binance to lend your Nano to short sellers, making it easier for an actor that has vested interest to attack the network, and potentially hurting the price.

Be proud of your Nano!

And finally you should be proud to actually own the currency of the future! Buy stuff with Nano (usually at a discounted price)! Send it to your friends to split a bill. Send them back and forth until you become tired!