What is an aspiring actor to do about extra work? The 'old school' take on someone working as an extra was that they were hurting their chances to become an actor, because extras did not act, they were just scenery. But the Screen Actors Guild took extras to a new level, including them in their union and disbanding the Screen Extras Union. Now a SAG extra is treated as well as a SAG principal actor. The extra does not make nearly the same money as the 'speaking' actor, but he has the same protections and priveleges.
Some people still think that if an actor does extra work, he will be categorized as an extra and never get a speaking role. That is simply nonsense. What every aspiring actor must do, of course, is to seek employment in SAG films. While indy work is nice and in a few cases pays a little, there is nothing to compare with union sanctioned films. Indy films just don't have the ability to pay and offer you the best working condiditons. Always seek SAG or AFTRA work for film and TV.
Once we get over the nonsense that extras are not actors, there are other benefits in working on a SAG film as an extra. If you collect three vouchers that say you have worked as an extra on three SAG films, you become SAG eligible and can join the union if you want to.
Then, when the aspiring actor is SAG eligible or joins SAG, the temptation to take SAG extra work is high. It offers good pay, which aspiring actors always need. But for those whose goal is to become an established speaking actor for film and TV, extra work can become troublesome. An aspiring actor does not want a resume that is all extra work. If he or she is SAG or AFTRA, then they should be racking up some speaking roles.
In summary, extra work is honorable and has advantages, but it still holds the pitfall of the actor becoming known only for extra work if he or she does not get out and get some speaking roles.