For most people using tabs, the additional information is not needed as you are most of the time not aiming for an identical replica of the song. You might play it slower or faster, different key, remove sections, etc
On the other hand I think tabs actually do strive to be an actual replica of a song. That's why there are so many versions of the same tab that broadly sound the same, from people trying to get as close as they can by ear to the recording.
