i am not really sure how tempo has translated into the new engine.
however, in the old engine, the effects absolutely were not limited to just the effect on the clock. for example, an uptempo team's fg% were impacted significantly. there were two mitigating factors. on one hand, the increase in tempo resulted in more fast break ops, which are higher % shots. on the other hand, the hurrying resulted in poorer shot selection in the half court, which caused lower fg% in that case. depending on the two teams, this could mean fg% could increase slightly (usually not too much), or decrease significantly (usually a lot more than it could increase).