Percentages are useful because they communicate scale without deep context. Who knows what we are talking about at all with regard to 0.0015? What units are we

Percentages are useful because they communicate scale without deep context. Who knows what we are talking about at all with regard to 0.0015? What units are we using? Most people don't have the context necessary to evaluate what it means that we started at 0.0015 foos and are now up to 0.002. But the percentage abstracts most of that away: on some metric we care about, this intervention increased the output by 33%. That immediately suggests the scale of the effect, without requiring anyone to walk out into the weeds. Obviously this can and is constantly abused, but it is undeniably useful.