Should SE scale high end content difficulty towards the usage of SIM ?

[Valence]

I don't understand what this has to do with the point that I made.

Being able to practice part of something in isolation does not detract from the difficulty or consistency required to complete it from start to finish in one attempt. Adding a checkpoint would mean that you don't need to complete it in one attempt.

This was a jab at SE's design, not at your point.
The lack of checkpoints in a conscious design choice they do to artificially increase lifespan of progression and the time people invest into running the content (this was the obvious answer).