they're not SUPER important. honestly use the raidmax, it'll be fine.
A great case mainly does 2 things: the thoughtful layout makes your time spent working with it much more enjoyable, and it makes the finished product that much more visually pleasing both to yourself and your friends (I myself spend over $200 on silverstone cases).
but at the end of the day, if all you want is to get the building part over with and play games, a cheap case is perfectly fine. to be honest when I started building I basically had components in a cardboard box with a fan blowing at it