By achieving personhood the thoughtform will be given moral consideration, and perhaps even rights.
Does a thoughtform deserve personhood, and if so why? A good amount of practitioners that work with thoughtforms will give their thoughtforms personhood, while other practitioners will not give their thoughtforms personhood, and will do with them as they please. Many people assign thoughtforms personhood when they reach the state in which they can be considered a tulpa. This is usually done, because tulpas are seen as sentient entities, at least more sentient then the other thoughtforms that preceded it, and because of this they will usually be granted personhood. Some people even extend this personhood down to servitors. Other higher Spectrum thought-forms such as egregore, and God forms usually will always have personhood from the point of view of the people who interact with them from the very beginning of their creation.
Three main criteria a practitioner might use that would show whether, or not a thoughtform deserves personhood in their own relativistic subjective way would be:
This criteria states that a thoughtform would have personhood as long as they can feel pleasure, and/or pain.
This criteria states that a thoughtform would need to have 5 things in order to have personhood. These five things being consciousness, reasoning, self-motivated activity, capacity to communicate, and self-awareness.
This criteria states that a thoughtform would have personhood as long as someone cared about them enough to give them personhood.
Are thought forms persons, and if so why? If we do choose to give thought-forms personhood it would lead into even more interesting ethical questions for their use, and manufacturing, and is something definitely interesting to wonder about.