@nasebein: Pretty much! Basically kanji carry meaning, so 美子 literally means "beauty" and "child," but leaving it in hiragana makes the meaning for "yoshi" more vague or up to interpretation. For instance, instead it could be 祥子, 欣子, 佳子, 淑子, or even more possibilities, with all the first kanji in the compound meaning something else (auspicious, graceful, good, etc.).