That leads you to often looking up trascription. Shift can be used to skip text forward but it's easy way to accidentally skip more than one line. Left mouse button seems to be the only way. Seriously? No text speed slider in a visual novel? wtf? With home and end to scroll instantly to top and bottom of that talk scene. The problem is that most game developers don't bother to design proper shortcuts and instead go forward with “whatever works” attitude.
Not a problem in itself if the proper keyboard shortcut design is utilised. Take an example from Blizzard who develop nothing but good UIs for their games. This stuff is over 30 years old and still some game developers ignore it. Instead F1 opens the ”main menu” which is against the traditional IBM set CUA standard for help menus opening from F1 key. Neither F10 or Esc open the ”main menu”.