Another thing to keep in mind are withdrawal fees are those are not negligent at all, especially since you mentioned that you wanna use your crypto to pay for stuff. For example, both Kucoin and Bybit have 0.0005 BTC fee.
- Guide to check fees: Taker, maker, deposit, withdrawal, transaction fees
- Withdrawal fees are different among exchanges so make sure you choose good exchange with acceptable withdrawal fee. Exchanges try to unofficial charge you multiple fee when you withdraw your coins, including fee for withdrawal apporval/ processing, on-chain transaction fee, platform maintenance fee, fee for consolidate inputs from user deposits, etc.
- In reality, they get lot of money from withdrawal fee as you can see in Old story. Exchanges get profits from users' withdrawal fees.