Template7 app data

I’ve gathered from the docs that this isn’t possible, but im wondering why i can’t access app.data with template7, why must all data be provided on init via template7Data: ? Accessing app.data something like {{…/app.data.username}} would be extremely helpful for my application.

If v2/3 you can access it like $root.username in Template/Component pages

So for example

{{app.data.user.username}}
should be
{{$root.user.username}}

?
This dosen’t work for me.