A "massive over-investment of time", indeed, unless you are doing it for college credit ;)
As for understanding the culture you live in, the historical cultures documented certainly differ from modern ones. It still provides a basis for some interesting comparisons between the Biblical books and groups that claim heritage from them.
His prose, though, I hate with the force of a thousand suns. I've never read a book so infused with insufferable wankery as "Wilhelm Meister's Lehrjahre".
Not to forget that Goethe himself considered his most important work his contributions to Physics, where he tried to argue that Isaac Newton was all wrong about Optics. Needless to say that Physics esteemed him less highly than Literature did.