An effective spurious argument is one that sounds valid to the audience that is not.
Sadly, by definition there are many more arguments available to someone prepared to use spurious arguments. This is because a dishonest or ignorant debater can mix spurious and non-spurious argument. Spurious arguments are more effective the simpler or more concise the discussion as there is less opportunity to discuss the flaws in the assertions made.
This means that one can overwhelm an opponent with many spurious arguments before a single valid argument is presented.