Unobtainable books spawning in chests

Usually of course i have a seen myself enter temples; jungle or desert to find myself a few precious minerals and the timeless bone and rottenflesh. But when i entered in a world i planned on doing a series on i noticed that there were nearly unusable and unobtainable by normal means. I tested it and reviewed a few wiki pages and it IS possible to create but it seems a little useless to have the two enchantments together as when combined with a tool in survival it will only apply the applicable enchantment (e.g. sharpness & protection will only apply sharpness to a sword).