A magic circle is used to create a tight circle of stitches at the start of a project, primarily in amigumuri. Using this method, you can minimise having any gaps or holes at the starting circle.
Whilst it is probably the most preferred option, it certainly is the hardest! A lot of people end up chaining 4 and joining into a circle because the magic circle takes some time to get to grips with.
When I was first learning crochet, I thought the magic circle was the hardest thing I had dealt with but I persevered, and lo and behold, it eventually clicked. Some tears and choice words happened along the way, but I think that is normal part of learning :)
Video: A quick visual of making a magic circle