Why is the complex number an integral part of physical reality?

In modern physics, the quantum wave distribution function necessarily uses complex numbers to represent itself. If physics defines the physical reality, then what we are saying by the statement above is that the reality is made up of immeasurable and undefinable complex numbers. In other words, the probability wave function or reality can not be understood natively as represented. To illustrate, let us consider a statement: there are i mangoes (where i is a complex number). The i mangoes statement can not be understood natively. However if I say i mangoes were distributed to i people then it makes some sense as i multiplied by i gives -1. But neither the i mangoes nor the i people makes any sense. In Engineering, complex numbers are nothing but a tool to calculate efficiently. The equations in engineering, which use complex numbers, can be rewritten as real numbers, but in Physics complex numbers are made intrinsic part of reality, thus making reality impossible to understand. My question is: assuming Physics represents the true physical reality, why does nature represents itself as complex numbers through the complex quantum wave function?