If you live a totally corrupt system, maybe.
But functional societies are based on the notion that cheating is bad, immoral, and nobody should do it.
"Now, what is more ethical, doing what benefits the people or doing what benefits such system?" - ha ha ... this sounds like how psychopaths in prison justify their crimes!
"I robbed the bank because the bank is evil, now who's more important, the people or the evil bank?"
No way around this one: cheating is bad.
Yes it is.
Maybe you live in an interesting developing nation?
Robbing banks, stores, anyone - is considered basically immoral in all of civilization, thankfully.
Yes - not all bank robbers are psychopaths - probably not the majority.
But prisons are fully of people bending reality to justify their crimes.
There is no ned to see any film about this.
Erm, no, it is regarded as unethical by almost everyone except bank robbers.
While true in general, cheating in that environment is also sometimes necessary to get on with your life unharmed. And sometimes cheating the system is actually regarded highly by the fellow citizens, because the people do not believe in the imposed system. Cheating is not beneficial to the system, but it often is to the people. Now, what is more ethical, doing what benefits the people or doing what benefits such system?