It is true that going on rounds and rounds of auditions is not necessarily the most productive use of the actor's time, however, the actor must accept auditioning as part of the actors' life (unless he forms his own theatre company that is). The actor can benefit from auditioning in ways other than getting the role though, and these benefits include: a chance to practice craft, talk about yourself, learn how to work with different directors and their approaches, plus it's an opportunity to win new allies, the actor may not get the part on this occasion but might in some future production if all goes well.
For the actor, the object of an audition is to obtain his own good opinion of himself, which is to say, that he conducts himself and performs the scene requested of him or reads the scene requested of him, to a standard which meets his own satisfaction. The actor should not worry about getting the part because that his out of his control, and the actor should not worry about whether the audition panel think he's a good actor or even if they like him, for this too is out of his control. Most actors will have experienced auditions where they've done the scene and thought they've hit the bulls-eye only to be greeted by an embarassed silence, and others where, at the end of the scene, they've hung their head in shame at the paucity of their effort only to be treated like a hero by the panel. Again, the actor's sole object in an audition situation is to obtain his own good opinion of himself, and all of his actions should be directed toward that end.
What happens if an actor is invited to audition, but upon reading the script realizes that he is the wrong kind of actor for the material, which basically means the material doesn't interest him, doesn't get his blood up, and that the actor probably wouldn't like himself playing the role. And this has nothing to do with playing an “unlikeable” character, an actor can revel whilst playing somebody like Hitler, no, what I'm talking about here is simply liking yourself, liking the work you're doing. When the actor likes the material he is working on, he is energised by it, can practice all day long, line learning and script analysis are not a problem, the actor cannot wait to show what he can do. Contrast that to reading a script which holds no interest, concentration is a nightmare, it is extremely difficult to follow the action, the stage directions become irritating, turning the page is a genuine effort. And, of course, the rules of auditions are no different to the rules of life generally: if it bores the actor at home, it'll bore the actor in the audition room, and he'll do less than his best, and what he'll get is not the part in the play or the film, but a bout of self-loathing, which may even cause him to turn against our most mysterious art form, and declare it worthless in an effort to be cleansed of the ill-feeling he has for himself.
If the actions engendered in the scene chosen for the audition mean that the actor cannot perform in the audition to a level which meets his satisfaction, then he should cancel the audition, regardless of the excellence of the people auditioning him, and regardless of the potential to enjoy those benefits other than getting the part. Of course, this is easier to say than to do, because auditions are hard to come by. Most actors are optimistic, because optimism is crucial if your life is spent battling against ludicrous odds, and, as such, many actors put a positive spin on a project that does not excite them in order to motivate themselves, and this is especially true when options are limited and work is scarce. But an audition is not work, an audition is the possibility of work, and a remote possibility at that. Why would the actor risk damaging himself by taking a long shot at a job he doesn't even want? It's just not a shot worth taking...... “Ah yes”, I hear you say, “but I have rent to pay, a CV to build, agents to impress”....Granted. But that, I'm afraid, is a subject for another time.
PS - The photo is of Jose Ferrer as Cyrano de Bergerac in the 1950 film version of Rostand's play, and would like to recommend Ferrer's performance as an example of great acting, a performance so true and generous, it is a joy to watch.