The way Superman-16 absorbs energy, for future reference, is sort of odd. On one level, it seems clear that he can absorb it like anyone else. For dramatic effect, however, he apparently likes to make it a tangible object, and then pull it in like a fishing line. But he just pulls it into his midsection, and absorbs it. It isn't like he eats it or something. The physicalization of energy before absorption is, as near as I can tell, just something he does because it looks cool.
The grabbing of the energy beams, however, is a different story. He wanted to use the energy-beams themselves as weapons. That's why he did it that way that time. The second time, with the radiation, he just absorbed it.