ATP is a very effective source of energy. Whereas glucose requires multiple enzymes to release energy, ATP only needs one enzyme for energy release and is able to release energy in small amounts as needed.
ATP can be used in different chemical reactions and thus it has been termed as the universal energy currency. When broken down, a portion of the energy released from ATP particles creates even more ATP , repeating the process of energy production.
ATP also aids in cell efficiency because it helps ensure that cells lose only minimal amounts of energy.