Line Lights can be used to replicate tube lighting and neon lighting. In the past they used to take a long time to render, but now they are as quick as any other light. Use a line light whenever you need a continous strip of light. There is no tool to use. You draw a shape you want and use a command to convert the shape to a line light.
There is some great protected information here that is only available to paying subscribers. You must be an active paying subscriber to see it, but you can Subscribe here.