Here, we discuss possible applications of the Casimir forces in micro- and nanosystems. The main part of this paper is devoted to actuation with quantum fluctuations and to the relative contribution of van der Waals and Casimir interactions to adhesion. Switching between the amorphous and crystalline states of phase change materials could generate force contrast sufficient for actuation, though for practical applications, the influence of protective capping layers and volume compression have to be better understood. Resilience against the pull-in instability is also a critical point defined by the material choice, dissipation in the system, and roughness of the surfaces. The adhesion induced by the Casimir forces is omnipresent, and it can play a pivotal role in unwanted stiction demanding deeper understanding. The open problems are the distance upon contact and the relative area of the real contact since both of them control the adhesion. An experiment designed to answer these questions is briefly discussed.