I wonder what that would look like.
If Takua thought "Hey. I'm hungry." And grabbed a banana, would the banana just vanish in some sort of dull flash, or would it liquify and be directly absorbed into the matoran?
And where does the line for "energy-bearing object" begin and end? Could a matoran get a quick snack by leaning against a tree? Could one matoran accidentally consume another with a hug?
Do they have to use their hands or can it be any part of their body? What's keeping them from consuming the energy from the very grass they walk on?
And could you imagine how terrifying this would be to outside species like the Agori? Sure freakishly tall warriors of destiny and rolling robo bugs powered by mind controlling flesh masks are weird. But the matoran, the most common residents of the Matoran Universe just casually have the ability to suck the life out of whatever they touch.