It is vital that you get an estate plan to avoid a costly mess for your estate, if you have minor children and something happens to you.
That is exactly the way in which many parents would choose to have their estate pass, supporting the thought that you do not need a formal estate plan. However, if those children who inherit everything are minors, then things get much more complicated as My San Antonio points out in "Minor intestate heirs pose expensive problems."
The problem is that it is not simple for minors to inherit anything. Courts are not going to direct that minors be given large sums of money and property to do with as they please. Someone needs to be appointed to manage the inheritance, for the benefit of the children. Every state has its own rules about how to appoint that person. However, those rules do not take into account what the parent might have wanted.
It is much better to create an estate plan that appoints someone to manage any inheritance your minor children might receive. This will allow the person appointed to be someone you choose and trust.
Reference: My San Antonio (May 11, 2018) "Minor intestate heirs pose expensive problems."