I do not consider Hafs or others as Kera'at or Quranic Readings. It is only one reading of the Quran, that what all of us are using. This is mentioned in the Holy Quran (75 : 18)( And when We read it, follow its recitation ).It is ONe recitation, no more.
The differences between the seven kinds of Readings are very minutes, they are actually in some Quranic words that do not affect the Quranic meanings.
Most of Muslim thinkers and scholars know nothing about these traditional Readings of the Holy Quran ( Kera'at ). Any Arabic Muslim can understand Quran without those called Kera'at.