The Quranic text we find written in normal mushafs is a product and combination of two aspects of the Quran's tradition of preservation.
The first is the rasm (i.e. consonantal skeleton) which was written and the second is the qira'ah (recitation) which was oral.
The rasm is the original consonantal text that was written by Uthman (RA)'s council of scribes and Quranic reciters. Muslims generally intend to be faithful to this original rasm.
However, the rasm is definitely not enough for modern people to be able to recite the Quran properly (nor was it enough for people in the past). It has no dots or vowels and it often drops letters that would be assumed or letters that would differ in dialect (so that both dialects can be recited within the text).
The Qira'ah or the oral tradition of Quranic reciters is what essentially informs us on how exactly the rasm should be recited. And there are multiple different recitations, and the reason for the different recitations is the Prophet's teaching of the Quran in different forms to allow the different Arabs of different dialects to have ease in memorization.
The recitation we generally see (and the recitation the text you quoted is based on) is the transmission of Hafs from his teacher Asim.
So, when the Quranic text is written for modern use, it tries to be faithful to the rasm of Uthman (RA) while still showing you how to recite the recitation of Hafs. To do this, the writers have to add things like consonantal dots, diacritics, and some letters that were omitted from the rasm.
But, they still wish to be faithful to the rasm of Uthman, and the dots and diacritics don't really affect that rasm. As for adding omitted letters, that is more problematic as that would be messing with the rasm itself. That is why when adding a letter for the sake of recitation, they only add it as a smaller thing that is not connected.
The hamzahs you see without seats are the result of this. Those are letters added for the recitation without being in the original rasm.
The reason the hamzah is not in the original rasm is to allow for different dialects of the word أَرَءَيۡتَ. Some of the Arabs would abbreviate أَرَءَيۡتَ into أَرَيۡتَ. This is represented in some of the recitations of the Quran like the recitation of Kisaee.
And Allah knows best.