Your customers get answers about your business at any hour, and those answers come straight from your own site. It's $49/mo, and you can add it whenever you like.
Every answer comes from your own website and documents, and links to the page it came from, so anyone can check. If something isn't covered there, it'll say so and point the customer to you.
Evenings, weekends, while you're out on a job. Your customers get a straight answer whenever they happen to ask.
It's $49/mo whatever happens. A brilliant month full of enquiries costs you exactly the same as a quiet one.