We eat the simanim on Rosh HaShana night, and daven and ask HaShem for whatever that particular siman is about. It is worthwhile to read the words of the Mishnah Berurah in 583:5, “Now, we do all these things for a siman tov, therefore, it is self-understood that a person should be very, very careful during these days (of Rosh HaShana [ed. note-possibly all of asseress yemei teshuvah]) not to get angry, not to lose one’s temper–besides the prohibition itself of that bad middah, we are looking for simanim tovim, and a person should therefore practice being cheerful, calm, and in a good mood.”
The buying of kibbudim on Yomim Noraim is a time-honored tradition, and is a great zechus for those who “buy” one. Nevertheless, one should certainly be careful to maintain the atmosphere befitting a Beis K’nesses, and the prohibition of “kaloos rosh” (levity and lightheadedness) certainly still applies.