Chaums ecash did not fly at least in part because nobody had solved the unconfiscatable, scarce digital commodity problem, there were no reliable sources of value on computers.

That Bitcoin and Lightning were invented makes dipping in and out of ecash possible, and makes Chaumian ecash suddenly a useful tool and solution for different problems than BTC and LN. 

Its IMO (maybe even in its current highly beta state) at the very least useful for local meatspace or trusted networks where you have small transactions, interactions and need to keep score. Caution obviously should be taken with it, balances kept low and temporary and trust (between mint&user) is necessary and not minimized in chaumian ecash. Even with its drawbacks I think it could power the thriving of circular economies, it's quite a good replacement for normal cash or (trad)Bank-transactions.

Maybe a bad analogy could help illustrate: if you have an induction furnace and an oven for cooking your meals inside in a safe, reliable and comfortable way where only major fuckups get you burned, you might still want to add a barbecue. Although its harder to get the meal right, you then have to be outside and are more likely to get burned or get wet a BBQ is still not a useless tool. I think its clear whats what in the analogy? For the right job, circumstances, and with proper handling, something which is otherwise not very good can be a delightful tool.