if the variable contains 1 as value which should lead to hide the table you will need a condition like:
if($(var) = 1, false(), true())
Therefore it might be better to change the variable-value to 0 which is the same like false() and meant that as condition it is enough to use:
tresesco has pointed me in the right direction, I should have thought of it myself: At some point, I had pressed Ctrl+Shift+S to make all objects and sheets visible - that is why, of course, the visibility_condition is not being processed ... ;-)
What I usually do to prevent this - but I obviously haven't done that here - is, I create a simple textbox with a text saying that currently all visibility_conditions are being overruled, and I give that object the visibility_condition >>1=2<< - that way, that text will only be visible if all objects are set to show.