For the past four decades, Physicists are trying to come up with a theory of everything that would unify four known forces of nature by combining Einstein's Theory of Relativity with Quantum Theory. The #StringTheory is an effort in precisely that direction. 
In addressing the question regarding whether String theory is worth that much, we can say that we have done good, we have not succeeded in our no.1 objective but over the course of all these years, Cosmology has made a significant progress and Physicists are still confident.
The discovery of Higgs Boson in 2012 in the Large Hadron Collider, the god particle that gives mass to every other particle is in itself a big achievement that has opened new avenues in particle physics and cosmology at large.
Unification was Einstein's dream and is therefore at least a 100 year old struggle. The past four decades have been in pursuit of string theory which is in fact a theory potentially explaining how weak, strong, electromagnetism and gravity can be combined in a single framework.
