Money.
Money.
But also because South America needs it.
One of these days, the money is just going to be too much to say no to. Especially considering that this is coming from the South American president as they see UEFA is starting to pull away from them. Brazil and Argentina falling off just a little bit has resulted in all European finals in 3 of the last 4 WCs, resulting in 4 straight European wins, something that has never happened before.
UEFA just launched the Nations League, something that looks like it will be a license to print money in the future, something that would make no sense for Conmebol as they only have 10 teams.
UCL gets bigger every year, Libertadores finally gets a spotlight on it and it gains press for all kinds for everything but the results ... and it looks like it might finally have a result, weeks later. We're still not sure.
They'll probably frame the proposal showing how much money it would make, and it would make plenty. Especially now in this technological era. But it makes more sense in terms of SA being diminished in the future.