For shy fish there is no pole waggling above there heads no slapping the surface occassionally, especially useful for roach. The waggler can also be fished at all depths of water from the bottom to a few inches below the surface so it is easy to follow the fish depthwise.
That's all I can think of at the moment but I'm sure other people can help more but I'm going fishing and its the end of school so a lot more where that came from
Fishing a Waggler when out of Pole range can be a lot more productive and sensitive than using a feeder, you can change the speed that the bait sinks, the depth you are presenting your bait, Fish for delicate lift bites and you can fish tight to islands and lilly beds with more finness/control and with far less disturbance.
Of course you will need to learn the different shotting patterns and why & when to use them but when the Pole can't reach the fish then the waggler is usually be the next best option.
But it depends on what water and species you are fishing for as well as the range you are fishing and whether there is a strong gusty wind or not.
I fished a lake today where there was a match on the opposite side of the pond. I was using the pole early on up in the water and had a few but I could see the fish were a lot further out. I put the pellet waggler on and got good access to the carp I could see. Alhough it was still tough it got some fish in the net and slowly but surely the match boys on the other side, none of whom were using this method, all started to switch to it and had a few fish too. Was very surprised that these match guys had not even given it a look in.
There is no doubt about the sensetive presentation of a pole rig,but I think fishing the pole has made many Anglers lazy.Put
the pole together,put on a rig,and off you go.No time spent having to fix up a rod,thread line through rings,shot up the float
orrectly,etc.etc. There are many young Anglers who have never used a rod,the pole is all they know.Both methods have their day.