This is somewhat correct: I clearly remember reading anomalous cases in law school about concepts like Holographic Wills and whether something as simple as “I leave everything to my wife” is a Will. A gentle reminder: I was reading these stories in a case book, which means these were matters that wound up being litigated. Having a clearly written Will (drafted without ambiguity and following appropriate formalities) helps with the avoidance of legal arguments that wind up in court. Estate litigation can be expensive (emotionally as well as financially) and time consuming as a way to determine who gets what.
You may have read about a recent case from New Jersey where the decedent wrote his own Will on his smart phone. Again, while this does show the ease with which the words can be captured, this case is noteworthy because someone had to opine on it. What is safest and least likely to produce arguments over your stuff when you die? A precisely drafted Will, duly witnessed and executed.
Further, there are many benefits of working with a team of professionals who can assess your needs and make suggestions, perhaps identifying issues that were not on your radar. For example, many people are unaware of various issues that arise from owning real estate in two states, or the differences between probate and non-probate property. Determining whether a Will or a revocable trust is the best option for you is something that your professionals can help you decide. Coordinating your beneficiary designations with your Will or trust and letting your financial advisors know your plan is all part of a thorough process to make your wishes a reality in an efficient manner. Further, getting advice from a professional can make everything from incapacity planning or charitable giving plan to helping figure out what to do with Fido easier.