Great answer.
It creates an historic link between the Mwami's and the current president and makes him a member of the royal clan.

I just made some research and found some interesting websites about Kagame's royal linkage: http://www.orwelltoday.com/readerrwandaqueen.shtml AND http://www.orwelltoday.com/kagamerwandareturn.shtml

Most relevant among all: "His (kagame's) mother, Asteria, was a sister of the late king's wife, Rosalie Gicanda. King Mutara Rudahigwa had died in Burundi in 1959 and his successor, Kigeli V returned to Kampala in 1972 and was able to offer moral if not material support to his relations in exile." according to Sharangabo Rufagari.

I did not know about his father's suicide. Surely due to the living conditions in the refugee camps.