It is important to have the correct bond angles of the different atoms and the shape of the molecule due to following reasons;
Among other properties the polarity of compounds mainly depend upon the shape and bond angles of that particular compound. For example, considering the molecule of water, we already know that it is a polar molecule with partially positive hydrogen atoms and partially negative oxygen atoms and acts as universal solvent. The bond angle in water is about 104.5° with a Bent geometry. Unlike carbon dioxide (CO₂) which has Linear structure with bond angle 180° and is non-polar in nature therefore, the bent geometry in water is responsible for the polarity.
Other properties which can also be predicted by predicting the bond angles along with molecular geometries are;
i) Magnetism
ii) Phase of matter
iii) Color
iv) Reactivity
v) Biological activities e.t.c