I'm not sure that I follow your points precisely. However, if my comments are not specifically relevant, please do post again and I'll try a second time around
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[color=blue]I think you'll arrive based on your speed and conditions.[/color]

This appears to be a motherhood statement with which we would all concur ?

[color=blue]The E6B handles this automatically, but understanding the concept is crucial.[/color]

If your E6B reference is to ETAS, then it is definitely incorrect. The E6B/Dalton solution involves the basic triangle of velocities which is solved by very simple and straightforward geometry. It has nothing to do with the CR's use of ETAS. ETAS is of no relevance and has no part to play in the E6B's solution. As I showed before, you can manipulate the E6B's triangle drawing capabilities to determine the CR's H/W or T/W, X/W, and ETAS with a little bit of fiddling but those quantities have absolutely no relevance to the E6B's navigation solution. Any suggestion to the contrary is misguided and suggests that one has been sucked in by various CR nonsensical suggestions.

The various concepts involved in any of this stuff are important and of significant value to student understanding of what is what and what is going on in the various solutions. Perhaps not "crucial" but, certainly, quite useful in aiding understanding of processes.

[color=blue]For calculations involving COS on non-scientific calculators, use approximations or simpler methods.[/color]

I can't bring to mind any approximations/simplifications of great value to pilot work. However, you missed the point of my earlier posts. If you choose to use the CR device, then you have direct access to both sine and cosine functions as the modified CD scales present them.
That is to say, I can look up the specific values for sine and cosine directly on the CR. A good reason to use the CR for examinations.