Since LegalZoom does not provide legal advice, they can only provide general information on legal issues. In some instances, the guidance issued is by indicating that a majority of its customers have answered a question in a certain way. Because every situation is unique and most of their customers are not attorneys, the most popular answer may not be the best solution for you and your family.
Additionally, laws are frequently changing, especially in relation to estate taxes, and because LegalZoom is not your attorney, their disclaimer states that the information provided by LegalZoom "is not legal advice and is not guaranteed to be correct, complete or up-to-date."
If serious legal mistakes are made, you may never know because they will not become apparent until you die. Leaving the ones you meant to protect left to deal with the mistakes. Mistakes that can easily cost more to correct after the fact, than to do correctly the first time. Lawyers do more than draft documents, they advise you on the best way to protect your family and distribute your assets in accordance with your wishes.