Why do some Sheikhs in UAE and GCC not publically announce their marriages even if the wife is also a sheikha?

Her Sheikh husband did not announce the marriage publically which happened years ago, only to those present at the milcha and they did not have walima. Now people outside of their families and their milcha witnesses (at nikkah signing) know they are married. The female had an honorary representation at her nikkah where her wali signed with marriage by proxy. Culturally, why is it done this way in Arabian gulf countries like UAE, Saudi, Kuwait, etc. That the walima is delayed after contract signing and the wife is not seen at festivities??