I was doing some research and found many things.

• I discovered the scanline algorithm, it's something that I don't use and is not efficient and a slow process.

• The difference between ray tracing and other methods is only the way used to find the illumination sources that contribute to the illumination for each point of an object.
  How the source affects the illumination depend on only the illumination model that you use and not if you use ray tracing or not. You can have surface scattering with or without ray tracing.
  Ray tracing is able to find more correctly the illumination sources in some cases as with mirrors.

• IBL is also a fake method, the reason is that the illuminantion in a point not only depend on the intensity, it depend also of the angle of incidence. The image used mapped on the sphere or other shape only contains the intensity information with no angle information, that would be impossible to be stored.
  The equivalent of IBL in games are the light maps.

-  Ray tracing is unable to do a correct ambient or global illumination, in theory it would be able to do it, but the required computations would last forever.
The only way to do a correct global illumination is with radiosity, then you can use if you want, the radiosity generated maps with or without raytracing.

• Raytracing is unable to handle particles, smoke, clouds, fire, etc must be done by other means.

Stupidity also evolves!