
Different strokes for different data
Since I don't run a mega meta multinational, I've never researched it, but it makes sense that each cloudy provider has its strengths and weaknesses (although finding them goes beyond cloudy and into foggy or even pea soup territory).
But I suspect that Suckerberg's primary concern is making sure he has an appendage (let's say feet in AWS and Azure, arms in Google and IBM) because that lets him bully the clouds into discounts and perks with the threat of shifting his business among them.