In my opinion, the use of a technique depends on the individual and who created the technique. There are techniques that are designed to be used in all pairs, some are specific to certain pairs. Usually the technique that is only used for certain pairs is the design system of observing and studying the history of the market pair's patterns. For this reason the architect of the technique recommends the use of the technique only for pairs that are compatible with the technique. Because, the nature of each pair is different, starting from the volume and so on.