Advantages of this Method
Unlike projectiles, currents remain within the control of the user rather the all control of it being lost on release. Due to them being a continuous expulsion of chakra, the user maintains control of the technique throughout its entire use. Since the user maintains this control it enables Raiton to be used much more for defensive and supplementary reasons, rather than offense alone which is usually the initial misconception. The user following their chakra allows for them to construct armours, enhance weapons and use raiton directly from their body to electrocute anyone in the immediate vicinity of the user.Continuous expulsion of chakra allows for techniques to last far longer than projectiles since the total amount of released Raiton chakra has to equal to that of the technique's rank.
Disadvantages of this Method
This method brings just as many disadvantages in using it if not more. These techniques aren't suitable for quick counters to incoming attacks, they require a much more slower release than projectiles and so wouldn't work in most jutsu vs jutsu situations. A few techniques seem to be exempt from this disadvantages e.g. Chidori Nagashi but the overall idea remains the same.
Another glaring disadvantage is, whilst using the jutsu, due to it requiring a continuous release of chakra, a new technique can't be used until the 1st is finished. This becomes a problem for weapon enhancing jutsu, which will cease to be useful the moment the chakra flow to the weapon is removed to perform another jutus.
The final disadvantage to this method would have to be, that to flow a current, most jutsu require a medium of some sort. Flowing a current would need the user to use the ground as a way of conducting it, Nagashi requires a continuous release from the user's body and Wave of inspiration requires a body of water to be conducted along.
^^The last part might not count as a disadvantage but it just a observation i've had of these type of techniques.
Strategies and Combinations of this Method
Honestly, other than conduction into Earth/Water techniques, nothing comes to mind.
Definitely the most difficult of the three categories, but I’ll have an attempt anyway.
Unlike most Raiton techniques, currents have the potential to be used in conjuction with Earth techniques instead of solely against them.
Conducting Raiton along the earth without utilizing the penetrative ability of Lightning allows for the two elements to work with eachother, the earth becoming electrified and hence more lethal, whilst the Lightning has a suitable medium to pass through much more efficenitly.
When conducting Raiton in the earth or underground, its difficult for the opponent to simply neutralize it with a Fuuton technique, they would first have to break the ground itself. This creates a vast array of deployable tactics, especially against shadow users who are primarily reliant on contact with the ground. Streaming a continuous current of electricity throughout the ground to exploit their dependency on remaining ground borne is a fundamental way of exploiting the opponent’s weakness. Its similar to separating a puppeteer from their puppet, separating a shadow user from the ground essentially removes a big part of their arsenal.