Two cuisines can use overlapping spices and still produce dishes that behave nothing alike. A large part of the difference is whether the flavor base is a wet paste or a dry powder.
A paste carries water and cooks differently
Wet pastes made from fresh chilies, aromatics and herbs bring moisture with them. Added to hot fat, that water must evaporate before the paste can brown properly.
This creates a distinct cooking stage where the cook waits for the mixture to tighten and the fat to separate. The wait is not optional, and skipping it leaves a raw edge in the finished dish.
The payoff is depth, because the paste effectively fries rather than simply dissolves, developing flavors that no amount of simmering afterward will produce.
Dry powders release faster and burn faster
Ground dry spices have already lost their water and hold volatile oils near the surface of tiny particles. In hot fat they bloom within seconds.
That speed is useful and dangerous at once. Powders go from fragrant to acrid quickly, which is why recipes so often say to add them off the heat or with a splash of liquid.
Because they act fast, powdered spices tend to be layered through cooking rather than committed in a single early step.
Storage explains a lot of the split
Dry powders keep for months, so cuisines that developed around stored spice trade lean on them. Pastes are perishable and suit cooking where fresh chilies and herbs are available year round.
Climate, not preference, drove much of this. A humid coastal kitchen with a grinding stone and daily produce arrives at wet masalas naturally.
Indian cooking straddles both, using dry roasted blends in some regions and freshly ground wet masalas in others, sometimes within the same meal.
What this means at an American counter
A US supermarket sells the powder route well and the paste route poorly. Whole and ground spices are easy; fresh curry leaves, green chilies and coconut usually are not.
Frozen aisles at Indian groceries partly solve this, carrying frozen grated coconut, chopped chilies and curry leaves that hold their character better than dried substitutes.
A small food processor handles wet grinding acceptably, though a wet grinder or a heavy blender jar produces the fineness that changes a sauce's texture.
The two approaches want different pans
Frying a wet paste asks for a wide pan, so the surface area lets moisture leave. A deep narrow pot steams the paste instead and stalls the browning stage.
Blooming powders wants the opposite: a small amount of fat, contained, with the cook standing right there. A wide pan spreads the fat too thin and scorches the spice.
Understanding which of the two a recipe is asking for usually resolves the vague instruction to cook the masala until it is done.