I would broadly agree with you that life is better than its ever been - with the caveat that for an awful lot of people across the globe that is not true - and for many of those fortunate individuals with the time and money to indulge in such social media applications, why not?
I find twitter very useful for current updates on News items, science, medical and entertainment. I find Facebook marginally useful for similar reasons, and it has been both a benefit and a curse in reuniting me with people I had lost touch with.
Many people forget that twitter, facebook, these forums come to that are the equivalent of walking down a street, shouting out your opinions and thoughts by megaphone, and having them fixed there for all to see, for life. People are learning that fact, sometimes painfully.