Another advantage is they receive less fishing pressure. In fact, on my favourite small stream I usually don't see anyone. Many small streams are known only to a handful of locals who, not surprisingly, don't advertise their existence. Several common-sense tactics can help.
Small streams can simply be the headwaters of larger, better-known trout rivers.
Fishing sections farther upstream than you have in the past, because of their small size, might reveal better fishing than you imagined. The same goes for tributaries entering larger flows. Some small streams, however, have their own drainage areas. Topographic maps are invaluable for locating small streams and to give you clues as to how good they might be. For instance, if the adjacent area is sparsely vegetated or flows through an agricultural area and has been channelized, don't expect it to hold trout.