More details below. Makes possible very large aperture future space projects. Ground-Based Astronomy Meter class telescopes that are hand portable to observe lunar grazes, planetary and asteroidal occultations, etc. Reduces or eliminates the cost of permanent installations for education and amateur astronomy. Adaptive Optics for amateurs.
Lightweight optics are of crucial importance in weight and cost reduction.
Think about it. The purpose of the primary mirror in a telescope is to collect and focus the light. The telescope costs less and becomes easier to move around, whether in space or on the ground. The support structure must be more massive than the optics, since otherwise the telescope will be top heavy. The ratio of telescope moving weight to primary mirror is quite high.