Nice piece.

I’d comment that setting up an LLC is not needed for either getting an EIN (the IRS will create one for you even for a sole prop, and it’s just intended to avoid needing to share your SSN with clients). You can also open a business checking account for a sole prop with that EIN.

Where the LLC helps is that it provides some protection against business creditors, if e.g. you find yourself in financial problems and can’t pay your business credit card and/or continue to pay your business rent.

Another helpful aspect is that you can ask the IRS to tax your LLC as if it were an S corp, set up a formal payroll to pay yourself a salary, and not have to pay self-employment taxes or FICA on profits that exceed that salary.

Regarding the business credit card, you can as easily dedicate one of your personal credit cards to your business needs, and not use it for personal expenses. The advantage is that personal cards have more legal protections than business ones.