The sky is falling? Again? It must be Monday.
I don't see a problem with this --
if the final medium they select is capable of displaying the required text and graphics, has sufficient battery life, allows for annotations, and can minimize distractions (e.g. no texting on the devices).
There is nothing magic about paper, LCD screens won't burn out your eyes or steal your soul. Alleged problems with the South Korean educational system have absolutely nothing to do with textbook mediums. The cost savings of using ebooks are likely to be substantial, especially for literature texts that don't require updating.
Most of the industrialized world is going to wind up switching to ebooks for schools in the next 15-20 years, and South Korea is going to get there first. You might want to get mentally prepared for what is almost certainly an inevitable shift in education infrastructure.