You've spent the last hour trying to curl the 50kg dumbbell and you just can't do it. You walk up to the yolked out guy and ask him to show you how it's done, he picks up the weight and curls it with ease.
At this point its not really fair to say you curled those 50kgs, and you didn't get much out of the experience. Maybe you noticed something about his technique that helped, or he gave you some pointers, but you still can't lift the weight by yourself even with that information.
Now if you instead went back and trained some more at lower weights not only would you get more out of the experience (in terms of growth), but also seeing someone else do it is more beneficial since you can try it again yourself and directly apply what you just learned. Eventually with enough training at easier weights and progressing naturally you'll be able to lift the 50kg weights. But that one curl you're now getting to do for the noobie is in no way indicative of the time and effort you actually put in to be able to do that one curl.
Now if you're instead in a warehouse doing your job moving heavy boxes from A to B getting the yolked out guy to help you isn't that bad - sure you can't do it in the future but all that matters is that it was moved from A to B. If we take that same mindset into the gym we'll get nowhere since the gym isn't about moving something from A to B, it's about making you better at moving something from A to B.
Sometimes being shown the answer to a problem is just what you need to move forward, especially if you are inexperienced. Shown the answer with an explanation as to how you get to it is better.
You've spent the last hour trying to curl the 50kg dumbbell and you just can't do it. You walk up to the yolked out guy and ask him to show you how it's done, he picks up the weight and curls it with ease.
At this point its not really fair to say you curled those 50kgs, and you didn't get much out of the experience. Maybe you noticed something about his technique that helped, or he gave you some pointers, but you still can't lift the weight by yourself even with that information.
Now if you instead went back and trained some more at lower weights not only would you get more out of the experience (in terms of growth), but also seeing someone else do it is more beneficial since you can try it again yourself and directly apply what you just learned. Eventually with enough training at easier weights and progressing naturally you'll be able to lift the 50kg weights. But that one curl you're now getting to do for the noobie is in no way indicative of the time and effort you actually put in to be able to do that one curl.
Now if you're instead in a warehouse doing your job moving heavy boxes from A to B getting the yolked out guy to help you isn't that bad - sure you can't do it in the future but all that matters is that it was moved from A to B. If we take that same mindset into the gym we'll get nowhere since the gym isn't about moving something from A to B, it's about making you better at moving something from A to B.