Strategic chess can be taught with words, and adults will naturally lean towards the strategic parts. We respect our predecessors, we seek knowledge that has already been discovered. Alas, heuristics and such aren't worth very much to a Chess beginner, who will regularly make "simple blunders" (like putting their own pieces in a knight fork) until Elo 1500+ (a moderately skilled beginner club player).
And even then, Elo 1800 to 2000 will regularly put themselves in a position where they can be forked in two or three moves.
If you can manage to play a blunder-free game (much harder to do than it looks), that's when strategic thinking comes in. Knight placement in the center vs edge, or backwards pawns here and there, or whatever.
In part, I think children do best at chess because they aren't distracted by any of the myriad of books and research on the subject (which are... hopelessly irrelevant to beginners)