In terms of body text, typography isn't meant to attract much attention. The common reader shouldn't notice subtle differences. Bad typography is easily noticed

In terms of body text, typography isn't meant to attract much attention. The common reader shouldn't notice subtle differences. Bad typography is easily noticed and feels wrong. Good typography communicates as it should and doesn't command attention. Readers might not consciously notice differences, but they might feel them. Some poorly-designed blogs instantly make me feel claustrophobic. If they opened up the line-height on the body text it would instantly feel and read better. In the same way smaller differences in a font design can change its feeling, character and legibility. Type designers spend much time adjusting subtle nuances of a font to evoke a certain feeling as a whole.