The original poster asked what benefit breaking them up would have, they didn't necessarily ask for a benefit that's something lots of Americans would see as positive. America and its technology companies aren't super popular in many parts of the world in recent years, and people unfond of it would welcome progress in AI technology becoming less concentrated in the US. Maybe a more left-leaning Senator like Warren might see some benefit in power being more evenly distributed globally, rather than concentrated in a few big US tech companies.