Ok, dumb question. What is a "trust" for?
In a nut shell, a trust is a estate planning tool, in other words, assets you want to go to a benificinary after your death, goes into that trust, and it avoids probate. There is more advantages in doing a trust then doing a will. For one, a trust, unlike a will, can't be contested by others, if you have vultures in your family this is the way to go. Also there are some tax advantages to it as well.
When you put a NFA weapon in a trust, it's the trust that owns the weapon, not you. Same as you make a LLC, the weapon belongs to the LLC, not you. Only in a trust, it's a one time deal to set and that is it, you don't have to keep it up like a LLC, with keeping minutes, or paying to keep it "in good standing". The trust dissolves once you die, then the person who you left that NFA weapon to gets it. But that person can't be prohibited from owning a firearm, and he has to do the paperwork for the transfer, the transfer is tax free
Folks go the trust route, because it does not require a CLEO signature. Some folks hit a brick wall and can't get their CLEO to sign the form, even though there is no state or local law forbiddening them to own one.
With a trust, you don't need a CLEO signature, the photo, or fingerprints, you just mail the NFA branch the form 1, compliance form. and the trust along with the schedule A (list of assets) and 200 bucks