Why use float Type to store Descriptor Distances

[gitouni]

Please see here in MapPoint.cc.

I'm confused with why the author used float type to define a 2-D array Distances instead of using int type, since the function ORBmatcher::DescriptorDistance just returns int types. Furthermore, is it safe to straightforwardly give the pointer of float type Distances to the int type array vDists?

Could anyboday reasoning this operation? Any help will be appreciated.