That way, a dispenser could disenchant books obtained in bartering farms and others :3

Thats a cool idea, maybe it could even be extended to work with even more workstation type blocks like smithing table, cartography table, enchanting table, anvil,...

Not sure how the XP aspect is handled, but maybe it could require xp from xp bottles in the dispenser, and drop xp bottles when disenchanting for example.
Would be a automatable renewable way to get xp bottles too.