Use of higher kVp is:

Increasing the kVp increases the potential difference between the cathode and the anode, increasing the energy of each electron when it strikes the target. The greater the energy of an electron, the greater the probability it will be converted into X-ray photons. Increasing the kVp of an X-ray machine increases: The number of photons generated.  The mean energy of the photons.  The maximal energy of the photons. As the kVp of the X-ray beam increases, subject contrast decreases. Similarly, when relatively low kVp energies are used, subject contrast increases. Most clinicians select a kVp in the range of 60 to 80. At higher values, the exposure time is reduced, but the loss of contrast may be objectionable because subtle changes may be obscured.  White and Pharoah's Oral  Radiology Principles and Interpretation 8th edition