$900 is still far below the price level of even the bottom end range of interchangable lens bodies, never mind body+lens.
The bottom end for such bodies is around $1500. Add another $100 for a low end lens, or ~$1000 for a low end Leica level lens to match the $900 for the huawei.
You are essentially getting a free phone and camera with a (slightly worse than interchangable-level quality) leica lens with the P30.