Battery condition depends upon age/health of the cells and not liquid level inside. It is not really necessary that If some battery have enough liquid level upon looking at battery, it is perfect. That may die sudden too if life has ended or near to end.
I had same assumption for years which kept me on wet batteries until I started using maintenance free battery (Fujika) for 13 months now with no issue at all. But yes you may be right if battery is purchased from fishy dealer or problematic lot you may end up standing on road side seeking for help (All Auto Tans Car owner anyway must have jumper cables with them always).
Paani wali battery may bring corrosion to metal parts, bonnet etc due to fumes from acid. So having equal disadvantage. People in Pakistan don't accept new technology or may be pirated new tech 
is introduced here as most new cars abroad comes with dry batteries.
