When bobber (indicator 😆) fishing 2 flys, they can drift more naturally. And the top fly acts as an attractor. Sometimes way better than the single fly they are biting on the 2-fly rig. Egg and worm for example. Presentations without a bobber (indicator 😆) usually involves a fly mimicking a “swimming” bug right? I grew up fishing without a bobber (indicator 😆) and am quite deadly with it today. But it’s always with a nymph or wet fly. Both have there place and time.