Let's make an analogy. There are two empty fruit bowls in front of you. The one on your left has one piece of fruit. The fruit represents a will. A will performs one function only. It just states who receives everything when you pass away. That's it. A will does not avoid probate when you pass away and is completely public. Anyone can look it up from the court system while you are alive and after you pass. A will can also be easily challenged in court. This is process is known as probate, and can drain your estate by thousands of dollars. If your will is challenged, your assets could be frozen for years while in probate. Lastly, A will does nothing for you while you are alive.
Staying with the analogy made above regarding the two fruit bowls; the one on your left has one piece of fruit. However, the fruit-bowl on your right is full of fruit, and this represents a living trust. A trust performs several functions. While you are alive, it states who you want to make financial and medical decisions in the event you are incapacitated. This is the "living" part of a living trust. A will does not state anything applicable to when you are alive. A living trust is completely private. There is no involvement of probate at all and it is very hard to contest. Your assets are passed to heirs from a trust quickly. As mentioned earlier, think of the trust as a complete contingency plan for your life.
The answer is simple. A living trust prevents assets (like your home) from being seized by probate court upon your passing and is completely private. In addition, a quality living trust provides for a smooth transition of assets upon your passing by naming beneficiaries. Moreover, there is a reason why it's called a living trust.
If you are married, then someday, one of you will be left. If you are alone and later become disabled or hospitalized, the documents included with your trust state will have legal authority over your accounts and also will make medical decisions until you get better. Even better, you will have made all the complex medical decisions in advance. The person you chose to enforce your decisions will be required to do so. If you don't name someone in advance, then the courts decide who gets this authority.
The documents that help you when disabled are called financial and medical powers of attorney. This, again, is the "living" part of a living trust. A living trust is very difficult to contest. A good trust will have a "poison pill" (and ours does), which states that anyone contesting their share or contesting the trust shall receive $1.00. Lastly, a good living trust will name both a primary and secondary guardian for those with children under 18.
You have spent your whole life accumulating assets. If you set up a will, you may be putting your estate at the risk of being easily challenged in probate. A living trust sets up a contingency plan to help you for when you are alive and when you knock om God's door.