Acting is tough, competitive, nasty business. A good film role can start a career if the actor is ready to audition and appear on camera. The problem in this situation is the pressure it creates. Every audition counts.
Getting good auditions for good projects is tough. So when you audition, are you ready? And who helped you prepare and how did they help you? Much of what happens is cold reading and commercial trade.
In theory, there is nothing wrong with these courses – it would be better if they only warmed up or worked out in a certain location. You can also look for the best adult acting classes via https://rsmstageacademy.co.uk/adult-performing-arts-company/
The problem is that in people's minds they have largely replaced drama classes or actual drama situations where a beginner could learn the craft. People think they're up to the mentioned pressure because they go for a cool reading at a top-notch studio.
You are not. The conditions under which auditions are held, and then the conditions on most television shows and film sets, are uncomfortable for beginners or people who have done some cold reading to do a good job under pressure.
Good acting classes and good acting teachers recognize this reality and respond to it. They offer in-depth preparation for the real world of work in film and television.
Good acting classes emphasize technique and relaxation as the foundations of a successful acting career or even just a successful warm-up. There are several acting techniques out there you can consider.