What are the differences between the Echo and having Hydaelyn's Blessing? [Spoilers?]

[myahele]

I have a theory that only people who collected a complete set of Crystals of Light can then have the Hydaelyn's Blessing. Prior to that the more we collect the stronger our connection to Hydaelyn becomes.

The echo is capable of doing a lot more than just preventing tempering as we see throughout the game and what the Asciens can do.

So I do believe that the blessing is a tool to prevent Zodiark and his minions from doing stuff to us

It's been mentioned that we need alot of Aether to destroy Asciens, so maybe in the future we can actively tap into Hydaelyn's blessing and use that aether for ourselves?