Free money ...
In a world where money is free because they've been printing it for years then a whole load of stupid investments start to look sensible.
"The plan" is to take ARM's nice revenue stream and use it to pay virtually zero interest on the loan and pocket the rest.
Amusingly... this acquisition of the world's most successful chip company is about half financed by the sale of a "freemium" phone game... https://en.wikipedia.org/wiki/Clash_of_Clans
Now that's "added value" :-)