Obscure, yes because it's version 4.0.0 and it's around since 2006 and I never heard about it. New, no.
From the few examples in the README I'd say that it makes development more complex than using the usual server side rendering approaches. I'm also not sure Python is the best language for this sort of things. Better than Java but usually Ruby is better at DSLs.
Of course, there's the "just looking to build something (serious or not) and not concerned about it becoming a profitable business" group of people - like you, perhaps - and that's great! But it generally takes a lot of enthusiasts before a library becomes accepted as mainstream and a certain amount of luck is required for that to happen.