Battery charging is asymptotical. In the beginning, they accept quite a bit of charge current, and thus can charge quickly. As you get closer to fully charged,

Battery charging is asymptotical. In the beginning, they accept quite a bit of charge current, and thus can charge quickly. As you get closer to fully charged, the battery cannot safely have as much current pumped into it, so you have to back off on the current as you get closer and closer to fully charged. Bigger batteries, like in laptops, have multiple cells, to attain higher voltages, so that extra current can be directed to each cell. So, in short, no, USB-C won't let you charge phones all that much faster than at 2A