They cost far more (whereas physical books are heavily discounted for libraries), they have licensing terms (limited circ or time period), and there’s the issue of hosting perpetual access materials. Physical books are just cheap, durable, and most importantly yours to do whatever you want with them (donate them, sell them, make crafts with them, etc.).

Certainly not for public libraries

When Russia sought to ban PM in their country they used the same excuse as India (fake bomb threats). However, understanding that this can be done via different email services, just underlines that Russia and India are scared of their citizens taking their privacy back and perhaps even organizing.