Even deserts have ecosystems. See the section on flora and fauna in https://en.wikipedia.org/wiki/Atacama_Desert which in parts has been used for a stand-in for Mars.
The Qattara depression doesn't seem to be in the same league as the Atacama, as far as lifelessness goes. I mean, gazelles, cheetahs, vast wetlands?
It would also give millions of people in one of the most densely populated poor countries in the world a new place to live.
To me, that's an easy tradeoff. But I can see the other side of the argument.
Even deserts have ecosystems. See the section on flora and fauna in https://en.wikipedia.org/wiki/Atacama_Desert which in parts has been used for a stand-in for Mars.
The Qattara depression doesn't seem to be in the same league as the Atacama, as far as lifelessness goes. I mean, gazelles, cheetahs, vast wetlands?