Could you look at a few examples from the example tutorials under discussion?
https://online-go.com/learn-to-play-go/bl1-stretch/6
https://online-go.com/learn-to-play-go/bl1-stretch/9
I'm saying that this "correct move" is a middle-game error. Maybe its my 9kyu brain being bad here, but there's nothing about this tutorial (and many others like it in this tutorial series) that strikes me as a strategic error.
And I certainly think that nobi is a bad concept to teach if the tutorial hasn't covered diagonal moves, horse moves, 1-point jump and the like. Its not that "nobi" or "stretch" is a bad thing to teach, but its just one option in a sea of valid middle-game options.
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If the tutorial is going into things like this, it really should be going into at least the basic 3-4 Joseki and why various moves are considered good.
Agreed, no point in learning these nobi in the tutorial.
The first one is indeed probably just a little bit worse than a jump.
The second one, I'd extend too: it strengthens white and black has to come back to live. You could think about the hane instead, but at worst black can play the cuts and come back to live at 2-2.