The aspect of independence is great. Right now, they can already see its massive potential when combined with limitless energy.
On one hand is an ultimate ability that separates them from the world and makes them completely invulnerable to damage and other external influences. On the other hand, it is an ability that makes it so that no amount of enemies can defeat them as long as those enemies are on the same level as them.
Both abilities have their strengths and weaknesses. The ultimate ability is active and is time-based. It is all powerful, as nothing should be able to affect them when it is active, but it can only save them when it is activated.
On the other hand, the Aegis shield is passive. It will lie dormant on their bodies for when they need it, but it can't save them from something that was already affecting them before they activated the shield.
