Is an acoustic guitar a good guitar for beginners?

Not really.

That is, an acoustic guitar is not any more of a "beginner's" instrument than an Electric Guitar is. It might be cheaper, and it may be quieter (or possibly not: you can practice an electric guitar without actually plugging it in, or with headphones), both of which are reasons parents might choose to purchase a child an acoustic guitar instead of an electric one.

If you learn to master an acoustic, then you will have an easier time learning to play an electric. This is simply because acoustic Guitars require more precision to make each note ring true.

Also: an acoustic requires more finger pressure and therefore more finger strength and calluses. An electric is easier on the finger tips, but is also more sensitive as far as technique. My best answer is to practice on both to develop the most versatility. But if sound is an issue, an electric is quieter if you don't plug it into an amp.