I've had a neps for several years (alata, I think....) and it is doing just fine. It winters in a greenhouse that stays above 50F and the plant and never really went dormant last fall/winter. It's growing luxuriantly now and producing numerous pitchers as well.
The question is an esoteric one: can the plant 'recycle' or make use of the fluid in the pitchers in a time of drought? Can the fluid flow be bi-directional? I'm sure there are occasional droughts, even high up in their native, rain forest environment. Having such reservoirs or built-in 'canteens' would be a remarkable genetic adaptation.