The answer is different for everyone. A personal Facebook page can only have up to 5000 friends. Many celebrities and big names in the business have many more people than that sending friend requests, so they need a business page.
I started a business page so I could have a page where I only address Greenlight business. It is another social media page to maintain. I don't advise it for people who don't have enough time as it is for social media. There are also issues with showing up on people's time streams when you have a business page.
If you are an industry professional who doesn't have thousands of friend requests coming in, there really isn't a reason to have a separate page. You can use your privacy settings if you only want family to see certain pictures.
Just remember that being professional on FB is of the utmost importance no matter what type of page you have.