Because this is "...nai bakari ka", the first clause must be translated in the negative, not the affirmative. "Not only is it not attractive, it isn't even safe." "Not only is it not expensive, (but) it doesn't take up much space, either!" A close relative is "dake de naku," which tends to have the first clause in the affirmative.
Completely agree with MikiSan. Let me give another suggestion. 彼女は歌をよく歌うにもまして、ピアノもっとよく弾けます。 MikiSan please review my suggestion.
Is this entry active? "Meaning" doesn't look correct. neg + neg ex#6550 Japanese make sense. ex#6810 Japanese does not make sense. suggestion1: 彼女はうまく歌えないばかりかピアノもよく弾けません。