My only fear with having everything centralized is that Google can decide you did something wrong and cut you out of so many important things in your life, without recourse.
I had a nice umatrix config saved to the cloud but it got deleted somewhere in the last one year (I had to temporarily switch to chrome). Did that happen to you too?
https://news.ycombinator.com/item?id=15989146 is just one example I found with minimal searching.