Sure, just like any other social media site, there's shitty parts. That's what happens when you allow the masses to generate content. But you know what's awesome about Twitter? You only see stuff from accounts that you follow. You can mute/block accounts that you never want to see. The content is 100% up to you...dislike a content type or source, and you can easily remove it from your feed.
I've used Twitter heavily for the past three years. I'd gladly pay a low ($1-$5) monthly amount to use it, especially if paying would remove stuff like promoted tweets (which I currently kill with an adblocker).
I agree, tweeting about buying socks is pointless, just like a facebook status update about buying socks is pointless, or a tumblr post about buying socks is pointless. The medium of communication has zero to do with the pointlessness of any given content.
The vast majority of the info I get from Twitter is more along the lines of "High-severity bug in OpenSSL allows attackers to decrypt HTTPS traffic --> link" and "Titan Souls is great example of picking small target audience and making a perfect experience for them. Great example for new devs." than it is about who is taking a shit or buying undergarments.
Twitter may not have any value for you, but that doesn't mean it doesn't have value.