Optical computers are perfectly feasible but don’t benefit much from all the investment already sunk into microelectronics.
Neutrinos’ interaction with normal matter is mediated by the (aptly-named) ‘weak nuclear force’. All the actions of the electromagnetic force are accomplished by virtual photons (which are exchanged between the particles that are interacting) which are mass-less and can travel an arbitrary distance. There are three particles that do this work for the weak nuclear force, the positive and negatively-charged W particles and the neutral Z particle. They are quite heavy, which limits the range the force can act. Also the coupling constant, the chance any moment a neutrino will emit a virtual W or Z, is tiny. By comparison the coupling constants (actually they vary with energy, given here for “low” energies) are strong force = 1, electromagnetic force = 1/137, weak = 1×10^-6, gravity = 1×10^-39 (although gravity’s coupling constant is so tiny, the graviton is mass-less so again the force is long-range, which is why this force is so much more notable than the weak force).
Another strange aspect of the weak-nuclear force is that it is “handed”, i.e. it breaks mirror symmetry. Strangest of all, despite of all this it is a twin of electromagnetism. Raise the temperature to 10^15 K and the two forces unite into the electroweak force.
More than 50 trillion neutrinos from the sun pass through your body each second, and the vast majority of those go on to pass completely through the earth without interacting with it at all (or the other way around, through the earth and then through you, at night!).