Null object design pattern Vs null object check

Why Null object Design pattern is better then null object check. If we look at memory footprint in Null object design pattern we create a new dummy object of same type.which show if we have object of big size and large number of nullable objects in search query ,this pattern will create that much number of null object which will occupy more memory then a simple check which for null which my cost ignore-able delay in performance.Null Object design pattern