The difference over an entire octave is the main issue. As a LH bass player, octaves are played quite regularly, and when your hand is stretched to the proper distance after years and years of training, and you miss the target note ... it leads to frustration, bad sound and lack of concentration.
All bad things in performance.

It's not a minor difference ...
It's a huge diference. Sometimes it's the difference between a wrong note and a right one. It's one thing to rest your hand down in a chord position every 4 or 5 beats with plenty of time to switch to the next chord, but it's entirelly different when you are playing manual, complex lines with the left hand and full, multi-note chord patterns with the right (almost like a counterpoint lesson)....and missing your mark because the notes that SHOULD be there .... are 1/8 of an inch a way.
Makes me nuts.
Almost as much as the misuse of your/you're.