It allows for looting the national treasury today.

All large construction projects in Egypt go to the military first. Who then subcontracts it out, essentially paying the generals their cut. Hence why Egypt is building their new capital city, to placate the military elite.

The new capital is also to riot proof their capital. Large dense cities are hard to defend with armies. Hence Myanmar doing the same, even China is building a mini capital to the south of their existing capital.

That being said, this big museum does make sense. Egypt is tourism dependent, and it needs star attractions beyond the scammer infested pyramids. Egypt's reputation amongst tourists has taken a horrible dent due to the extreme concentration of street hagglers, and it needs all the help it can get.