The sentence makes it sound like the reason that it is preferred for real-time applications is because of the Hamming distance.

Perhaps something along the lines of

```
Unlike BRIEF, ORB is comparatively scale- and rotation-invariant while still employing the very efficient Hamming distance metric for matching.  As such, it is preferred for real-time applications.
```

If the above sentence isn't used, then "allows to emply" should change to "allows the use of" or some such.