Well in both cases people died, as the verse describes a battle. And the verb qatala قاتَل -qira'a/reading of the scholars of al-Kufa and imam ibn 'Amir and imam abuJa'afar according to al-Qurtobi- doesn't exclude that somebody would die as it is in the case of qutila قُتِل. In the case of the qira'a of imam Nafi' (and all other scholars) many of them died, while others remained alive. In both cases those who die will get a reward in the hereafter and those who remain alive will get a reward in this life and in the hereafter.
In summary all people involved in this battle will get two kinds of reward or at least one of both rewards. In this verse the "wa وَ" must rather be understood as an "or" than an "and"!
Note that the differences in the readings in the verse (3:146) reach more than 5 if we only take a look on how
was read imam al-Qurtobi quoted for this four plus an additional fifth linguistically "correct/conform" different Arabic readings:
كَأْيِن (ibn Mohayssin ابن محيصن)
كأيِّن (Majority) however in the recitation some of the scholars like ibn 'Amr and in a report al-Kissa'iy made a pause at كَأَيْ.
كَائِن (ibn Kathir ابن كثير)
كَئِن (ibn Mohayssin)
this could easily reach 10 or more options.