The short answer
If your Facebook page keeps you as busy as you want to be, you may not need a website yet. Facebook is very good at keeping in touch with people who already know you. A website does a different job: it helps people who have never heard of you find you when they search.
What does Facebook do well?
It is free, quick to update, and your regulars are already there. For today's specials or a last-minute appointment, nothing works better. If most of your custom comes by word of mouth and you are as busy as you would like, that may be all you need. I would rather say so than sell you something.
Where does it fall short?
Mostly in three places.
People who are searching. Someone new to Inverurie who types "hairdresser near me" into Google is shown websites and map listings first. A Facebook page can appear, but usually further down, and not for every search.
People without an account. Facebook often asks visitors to log in before they can see much. Some people simply close the page.
Finding the basics. Your prices, menu or opening hours get pushed down by newer posts. A visitor has to scroll and guess which post is still correct.
Is the page really mine?
Not quite. Facebook decides who sees your posts, and it changes its rules without asking. Pages do get locked or hacked, and getting one back can take weeks. A website on your own domain name stays yours whatever happens elsewhere.
So which should I have?
They do different jobs, and they work well together. Keep Facebook for news and conversation. Let a website hold the things that don't change every day: what you do, what it costs, where you are and how to book. Then link each to the other.
A simple test: ask your next three new customers how they found you. If all three say Facebook or a friend, you are doing well with the people already close to you. A website is how the ones who are searching would find you too.