HT won't "help" gaming, but it prevents a problem from not having 4 cores if a game demands 4 cores.
The i3 is typically clocked really high as well compared to an i5 (at base clocks) so it performs the same in all desktop tasks if not better, and it shouldn't be a huge limited factor for games.
The Pentium g3258 is a popular dual core without HT, and it has problems when games start to demand more than 2 threads because it only has 2 threads available, and it's also nowhere near as fast as an i3.
The i3 is the best bang for your buck CPU.