Why you should build your own following...
1. Authority!
Again, having a massive following helping in so many ways! Authority is just one.
Think about it...
If your client was looking for your services and your competition had a massively following and you had none. The main thing that shows is that they do this much more often than you and they clearly do a much better job as they are so popular.
More followers mean more authority. It makes you more trustworthy. And makes you seem more efficient at your job/service.
It's very much the same as if a company had a bunch of good reviews online - clearly, they are good at what they do!
2. Better reach!
Facebook has changed its algorithm and now your organic posts (the ones you post on your regular page, not ads) will only be seen by 1 - 3% of your followers.
This means, that if you only have 1000 likes, most of your posts will only be seen by 10-30 people! (Not like by that many, only seen!)