Rules are useful descriptions, but they are not the only learning object
A rule can explain why a form is grammatical and can compress a large number of examples. That is valuable. The difficulty appears when a learner can repeat the rule but still cannot assemble an expression quickly or select between several grammatical alternatives in context.
A Frame keeps more of the actual language visible: fixed words, open slots, ordering and constraints. It sits closer to production while still being more general than one memorised sentence.
Metkagram organises practice around decisions
Instead of stopping at “use construction A in condition B,” Metkagram can place A beside a nearby Frame and explain the Contrast. A Choice then asks which option fits a new situation. The learner practises the boundary where a real mistake can happen.
That approach is particularly useful when both alternatives are technically possible but differ in meaning, stance or register. A rule remains part of the explanation; it simply no longer has to carry the whole lesson.
The practical question is which representation helps the next sentence
Some topics need a concise grammar explanation. Others become clearer through several examples and a reusable Frame. A good learning system should not force every problem into one format because the interface happens to have a favourite exercise type.
Metkagram’s wager is that many B2–C1 problems benefit from moving between sentence, Frame, Move, Contrast and reuse. That is a product design choice to test, not a declaration that grammar explanations have become unnecessary.