Expected behavior
The idea is that when a special flag/configuration is enabled, unfocused windows would shrink by a given percentage. With i3-gaps it would make them appear more distant from other windows (the net gaps would be effectively bigger) which would make the focused window stand out even further, as it would appear to occupy it's space more aggressively.
I thought of this as an alternative to actually changing the gaps, because actually resizing the windows might trigger layout changes.