But familiarity gets more remote as you need larger and larger (or, smaller and smaller) multipliers. It's far more illustrative to say "the volume of a typical gas tank" than "the internal volume of hundred million poppy seeds", even though the volumes are in the same ballpark. For example, https://en.wikipedia.org/wiki/Orders_of_magnitude_(voltage) says that high voltage substations are in 100 kV range and 25.5MV is "The largest man-made DC voltage – produced in a Van de Graaff generator at Oak Ridge National Laboratory" and gives me much better color than a "comparison" with 100 million batteries. (By the way, 100 million batteries stacked together is a bit over the length of one marathon - how many readers could easily tell you that just from the description alone? Much better to measure many lengths in marathons than 10^8's of battery lengths!)