Well light is a form of energy, it is basically form of radiation. It just has very low-energy density, and cannot penetrate objects, not partly or fully.
Like x-rays go partially thru human body, but stops into lead-sheet. And gamma-rays go thru anything and everything.

So electricity have been transformed in to light, you are correct. But this isn't the case with the micro-processors.
Information can't be measured as an physical unit, it doesn't have mass or anything that can take the energy that could be imaginable.
So everything turns in to heat.

And energy efficiency of lightning surfaces have been improving but it's nowhere near 90% efficiency.
If you compare led or fluorescent-tubes to light-bulb they consume 80% less energy to give the same amount of light.
It doesn't mean that 90% of the energy is transformed into light. Just touch the fluorescent-tube or led, they are still quite warm.
Powerful led's can still burn your fingers. And heating anything takes lots of energy.

Just face it, the world today is very inefficient when it comes to use of any sort of energy.