"But really, having the business account did not give me anything I would not have gotten by opening a regular account, except a debit card with "Business Debit Card" printed on the front."
It did one very important thing. Your personal finances and your business finances (LLC, LLP, INC people only), are no longer co-mingled. You have thus limited your personal liability and shielded your personal assets from business liability. (IANAL, not legal advice).