They're fine for Neps. In my experience they actually dry the mix out faster than plastic. The sides of plastic pots act as a barrier to evaporation. Fibre lined baskets allow for evaporation across their entire surface area.

Didn't think of that. Thanks for the info.

Yeah, just make sure you keep the soil moist all the time. Nepenthes don't like to be dry either, so too much evaporation would be bad as well. It is a balancing act with these plants. Mostly it is standing, stagnant water in trays that Nepenthes hate.