Ah, I remember that convention from my youthful electronics-hobby days! I always assumed that the idea was to reduce the risk of misreading due to overlooking

Ah, I remember that convention from my youthful electronics-hobby days! I always assumed that the idea was to reduce the risk of misreading due to overlooking the decimal point (or interpreting a random speck of dirt/ink/whatever as a spurious decimal point), particularly in potentially-untidy hand-drawn schematics. But maybe I'm inventing that explanation out of nothing at all... I don't have any supporting evidence, it just seemed plausible to me.