Guild Wars 2

The question I am asking myself currently is:
Is it more rewarding to create a new account and register the addon on this one or should I register the addon on my current account?

The point is:
As far as I understand I am just getting access to the new content when I register the addon on my existing account. When I am creating a new one, I am getting 5 Character slots + bank + …

Do I get something for using my existing account?

You get to keep all your unlocks/account bound stuff.

If none of that matters then by all means create a new second account.
If you are unsure what all that means I’d research carefully first.

But I am definatley not getting anything from adding the addon to my existing account, except the new content?