from experimenting with using the Point and Spot Lights natural "Radius" slider I could never truly get the effect they produce to match up 1 for 1. instead of just adding it in anyways and forcing you to fiddle around with sliders all day I chose scale as a alternative. these lights don't use scale in any meaningful way so it was a good alternative to allow for a quicker tuning process to match as for when I used Radius it took me significantly longer to match the lights

Yes of course. each light is individually generated and you can also generate a collection of lights. However if you want all of these lights mixed together you'll have to do the Mix Color system yourself by default only the lights factor and Self shadow get combined with a mix color

technically yes and there's a argument for it to be used in Eevee. it separates each light individually in your shader rather then getting combined like it does with shader to RGB. However the current Raycast node is how we create cast and self shadows and that has some known limitations for Eevee that I can not solve for unless blender fixes it themselves. Lastly the tool is designed mainly for Cycles use so that is where development is going towards anyway.