Generally, the type of electrode used depends on the material that is being welded. Then it is important which welder. And welding is a kaaaawal of solid knowledge. So in everyday life you need to know:
- basic electrodes - only for DC welding
- rutile - for e.g. the simplest "made" welding machines.
And in everyday practice, pink electrodes are used for simple installation of angles and other wires - usually in 2 thicknesses for thin and thicker things

The difference you noticed when switching from red to pink can be found on the Baildon website - the red one needs a lower voltage to strike the arc. And in a "made" welding machine, as a rule, you save on voltage in order to "force" as much current as possible from your core.
If someone understands at least the basic principles of welding, he can learn a lot from the electrode table itself (it is not necessary to know what rutile is

)