The article isn't clear at all on how this compares to existing paper cups.

Papers cups basically all have a wax coating on the inside so they don't absorb your coffee. Otherwise they'd obviously get soaked pretty much immediately. And wax is biodegradable.

Has anything prevented a waxed bagasse cup from being made before? Does the bagasse+bamboo combo still require wax, or is the advantage that it doesn't?

And if the bagasse is already being fully utilized as fuel, is this really going to be an environmental benefit? What will the sugar processing plants use as fuel instead? If it's oil (or coal), would this wind up being worse for the environment overall?

Technically this is interesting... it's just very unclear to me whether it's a good idea.