I wondered why he doesn't have a personal website and saw that Sergey Brin, Tim Cook, and Elon Musk don't either. Ended up at gatesnotes.com and signing up for Bill Gates' mailing list.
Shame to be sitting on something like that and not doing anything with it.
Not really. Especially not if you have Google at your disposal.
A personal website tends to serve as either self promotion or to voice your opinion. I don't think he needs promotion, so unless he wants to start blogging, it's only risk and timesink with no upsides.