Tabs' major appeal is that there's no learning curve: what you read is almost a physical representation of what you play. And it only requires a text editor to write, and can easily be published and shared on a website.
The best tabs are printed under a staff that contains the missing rhythm information (along with the actual pitches, etc., of course). Not exactly concise, but very info-rich.
As you say, most tabs don't include much information besides pitch and order, but can include guitar-specific ones, such as bends or slides.
It's possible though to write good tabs, such as the ones available in Guitar Pro (http://www.guitaring.info/uploads/software/Guitar%20Pro/Guit...).
Tabs' major appeal is that there's no learning curve: what you read is almost a physical representation of what you play. And it only requires a text editor to write, and can easily be published and shared on a website.