We consider the number of states and the number of transitions in Watson-Crick finite (non-deterministic) automata as descriptional complexity measures. The succinctness of recognizing regular languages by Watson-Crick (arbitrary or 1-limited) automata in comparison with non-deterministic finite automata is investigated, as well as decidability and computability questions. Major differences are found between finite automata and Watson-Crick finite automata from both these points of view.