Despite being on a continent, this point is almost in the middle of the very large Lake Victoria with, apparently, no view of land. Therefore, it is considered secondary.
While lying inside the frontiers of Tanzania (about 800 m south of the borderline with Uganda), the closest piece of land is Bukasa Island in Uganda, 80 km NW of the Confluence.
Note that land will be JUST below the horizon, so a "tall enough" boat and "good enough" telephoto MAY be able to show land and convert this to a primary confluence. No guarantees. :)