Considering you get a private room, well capsule, with both USB and a regular international socket that takes a plug from many countries (at European voltages) to charge your phone, powered devices and even a tv, then this is a really good bargain.
This doesn't have the most comfortable mattress and the design of the capsules might awaken the lighter sleepers among us due to the plastic being particularly noisy, but if that is unlikely to bother you then go for it.
I spent 4 nights there and would stay there again should I find myself in Bilbao again.