I think at the root of the question lies the issue of what are the goals of a bachur learning in Yeshiva is it
A. to gain the skills necessary for life long learning
B. to gain Torah knowledge
If its 100% emphasis on A then indeed a bachur should never touch an Artscroll. If it is 100% B then he should use it more often than not. Perhaps the goals of a bachur should be a hybrid of both with a bit more emphasis on A at the beginning of his Yeshiva career and more emphasis on B toward the ( projected) end of his career.
If no thought is given to reassess his gaols each year then any serious yeshiva student will be missing out. If a 9th grader can still say that “he is learning how to learn” with the same conviction as a 5th year kollel yungerman then we have a serious flaw in out system.