What is the reason and the meaning for kids playing with a ‘Dreidl’ on Chanuka, Should it be encouraged? Can adults also play?

A common reason mentioned by many is that the ancient Greeks forbade studying the Torah, so the people would gather together in secret. If the Greeks interrupted them, they would pull out the dreidels and pretend that they had gathered to gamble. (Minhagei Yeshurun ( 9: 4), Shefa Chaim 2: 283, Taamei Haminhagim and others) We find that many leading authorities of Ashkenazi Jewry played briefly the Dreidel game, including Chassam Sofer, Rav Meir Mifremishlan, the Tzanzer Rebbe and others (see Miminhagam shel Gedolei Ashkenaz, Chap. 3, no. 8; Siach Sadecha, Ki Tissa p. 164, Nitei Gavriel 51: n. 2). Peleh Yo’etz (p. 90) also notes that many Rabbonim of Ashkenaz and Chassidic communities played Dreidel during Chanukah, to publicize the miracle. In Chassidic circles the dreidel was treated with utmost respect, and many authorities write of the secrets latent in it. In his Laws of Chanukah (1:2), for instance, Rabbi Nasan of Breslev writes how the idea of the dreidel is to “descend in order to ascend,” allowing the righteous to reach a unique elevation on Chanukah. Others explained the nature of the game. The Bnei Yissachar writes that the reason a Dreidel is spun from the top, whereas the Purim gragger turned from the bottom, is related to how each of the miracles were effected. On Chanuka the miracle came from above, directly from Hashem. However, on Purim the miracles were brought about by the actions of Esther, Mordechai and the Jewish people from below. In a Different Light: The Hanukkah Book of Celebration, writes that a number of rabbis also developed elaborate numerological (Gematria) explanations for the Dreidel game, using the numerical equivalents of the letters on it. For example, the sum of the numerical values of nun, gimmel, hey and shin is 358, which is also the numerical equivalent of the Hebrew letters spelling Moshiach. the Hebrew word for Messiah. A more simplistic explanation for the adaptation of the custom is suggested by the Aveni Nezer (see Piskei Teshuvos, Vol. 6, p. 463). In his view, the custom evolved from the special atmosphere of Chanukah, when all members of the family get together for lighting the candles so as to publicize the miracle. To ensure that the children would not fall asleep, the dreidel game was canonized as a custom. Others, have argued that the letters nun, gimmel, hey and shin are supposed to represent the four kingdoms that tried to destroy the Jews in ancient times: N = Nebuchadnezzar (Babylon); H = Haman (Persia); G = Gog (Greece) and S = Seir (Rome).In reality, historians write that the Dreidel is not a Jewish invention, but is instead an adaptation of a centuries-old game played in many cultures.