They're not necessarily good for advice, but you need a decent amount of business knowledge to run even a small business, and LLMs can help with all the noob questions you'll have if you're starting a company and never went to business school.

"What's the difference between amortization and depreciation?" types of things. You could Google them, but you have to waste time skimming through a couple blogspam articles, but LLMs can explain the concept in an easy to digest way much faster.