I only formed a trust because of NFA stuff being easier to do that way AT THE TIME. Even during those times, another good buddy of mine already had a standard family trust. He was able to use that trust to do all his NFA firearms. He didn't need to do another trust for them.
Now, I do my NFA stuff as an individual because that's now the easy way.
The only advantage now of a trust is more than one individual being able to have possession of the NFA items at a time.
There may be a time when all your firearms need to be in a trust, when the .gov decides that they will get rid of firearms by outlawing transfer; current owner is the last owner. Then having a trust so ownership never changes may have its advantages. (Until the .gov goes further)