Is it a must to use "yes" while training a dog?

My family is gonna be getting a new puppy soon so lately we have been talking about a lot of puppy stuff in my house. But my sister has been annoying me lately because she is saying that while training him to do tricks and stuff, we can only use the word yes and not good boy because she saw on a reel that yes is the command when a dog does something right and good boy is to encourage them to keep up the behaviour. And she wants us to standardise the training commands to yes only. But I feel very restricted by that because I see no reason why we cant have a few commands to reward him with a treat. Like why does good boy have to be strictly for praising him to keep up the good work? If he does the trick right and just say good boy! And then reward him with a treat. Theres no difference. He can learn 2 phrases to know that that means he did the trick right? Am I wrong in thinking this way? Is my sister right? The thing is, he is gonna be an Australian shepherd so I know hes gonna be a very smart dog who most certainly will have the capability to learn 2 words for having done a trick right. But she is still so adamant on "standardising the training" like as if this is a military camp 😒😒 it frustrates me because I would like to have fun, playing and training with the puppy too but I cant do that if shes gonna always interfere with how I play with him and lecture me about how im doing it wrong and am gonna ruin his behaviour or something like that by not using her desired word to mark his good behaviour. Imagine im trying to make him learn self control by placing a treat on his paw and telling him to stay. So the main command is stay. But maybe I want to release him with the command go! How does that undo any training done with the command yes? Hes still gonna know that iv released him from the original command just based off my tone and energy. To me its all the same and I dont want to have so much restriction when it comes to training him. Please tell me if im wrong 🙏🙏