I have seen people in sulawesi performing trance in a travel show. In the following link you can see that.
From this link, I can see trance boosts confidence.
Just came across the following in google. It looks to me from the following link trance helped suffering people to express their sufferings, reasons and possible solutions to their superiors. When they are in trance mode, superiors have to listen to them anyway
The following link is the source.
Tamil Language and Murukan Worship in South Africa
Trance is a part of worship of Lord Murukan. Trance is an important factor which reinforced fear of doing wrong and inspired bhakti among devotees. Trance enabled Tamils to escape from their miseries, sufferings and difficulties under the hands of their own Indian supervisors (called sirdars) and white masters in their daily toil.
This is a part of Muruka worship where the devotee enters into another level of consciousness, losing his body-consciousness. During kāvaţi festival when he carries the kāvaţi singing Tamil songs, the devotee goes into trance. The abnormal behaviour of the devotee in terms of power, strength and knowledge conveyed in Tamil, developed fear on one side and faith on the other to many devotees of Lord Murukan. This is a direct experience between the trance person and the devotee, based on the questions and the answers exchanged.
Trance of this sort served like a ship carrying the devotees freely from their sufferings to a safe place. The trance person used to answer many of the questions raised in Tamil language by pointing out their mistakes boldly and even guided them, showing the ways of atonement with remedial measures. Sometimes the trance person called vēlan explained the reasons for their sufferings in detail to their satisfaction, bringing out their secrets which made them feel surprised, as nobody knew them.
The remedial measures varied from personal discipline to offerings to the temple. Some devotees were reminded of their forgotten vows. All these experiences increased faith and commitment to Lord Murukan. In addition to that, the trance person used to proclaim openly some of the secret information of the supervisors and masters who terrified them. The masters were afraid to punish those devotees and the trance persons as they feared retribution.
Sometimes the trance-person used to guide some of the masters when they had difficulties. So trance helped the devotees of Murukan as a protection and prepared them for their future through faith and devotion to Lord Murukan. In all these communications it was the Tamil language which was used and not English.
A French film maker Jean Rough did a study among a tribal community called Haouka (Songhay) and their cult in Ghana and documented how migrant workers resolved their adaptation to a colonial urban environment through trance. In the same way the Tamil migrants also used this trance in making adjustments to their lives suitable to their environments.
The following text is from this link.
It certainly appears that the men are not really in much pain. They are said to be in a semi trance state so they don’t feel it. I honestly think that the fact that they have been fasting for 8 days plays a big role in this whole piercing business. They are probably already hovering between reality and trance due to lack of food. Then you have family members chanting in your ears, therefore making you even more delusional. Finally, the fact that they have been fasting means that they have lost weight; their skin is already hanging loser than normal. It's the lose skin that is being pierced, which may be less painful. There is no (or very little) blood that I saw. The people doing the piercing do know that they are doing, they find the right pieces of lose skin and pinch them and pierce the hook through the skin, they stay clear of any veins - they are professionals!
However, I will admit that I never did see any sterilization of the hooks being conducted, so that was a bit disturbing, but no one really seemed to care.