The HIDA (LeDavid Emet, ch. 4, § 6) writes that it is customary to accord the honor of opening the Hechal to a Torah scholar, an elderly man or to a groom within thirty days of his wedding. The opening of the Hechal, he continues, has great virtue because it has the power to reveal many spiritual lights. The Arizal (Sha’ar Hakavanot, 48d) writes that opening the Hechal brings forth a tremendous spiritual abundance and that the more learned and pious the one that opened the Hechal is, the more abundance flows down. As such, he was particular about honoring Torah scholars with this great Mitzvah even if he had to pay for it.
The importance of Petihat HaHechal is exemplified by the Ben Ish Hai’s solution for one who, Heaven forbid, drops a Torah scroll. He writes (Rav Pe’alim, vol. IV, Orah Haim, § 28), quoting Rabbi Moshe Zacuto, says that in order to rectify such a situation is to fast, to donate 262 coins, to light a 24-hour candle in front of the Hechal in honor of the fallen Torah scroll and to purchase the honor of Petihat HaHechal.
Additionally, the HIDA (Yosef Ometz, § 57), Rabbi Eliezer Papo (Hesed La’alafim, § 135) and Rabbi Haim Palagi (Sefer HaHaim, 1:8) write that it is a Mitzvah to honor someone who’s wife is in the ninth month of pregnancy with Petihat HaHechal so that she should have an easy delivery. Just as the Hechal has two doors and two hinges, so too a woman has two doors and hinges, as it were, in her womb, and by opening these doors when taking out the Torah it is auspicious for an easy delivery.
Summary: Petihat HaHechal is a Mitzvah with many spiritual benefits.