I wouldn't have thought of doing it any other way. You can write, revise edit, craft; do everything in a format you're familiar with, then cut and paste into HubCapsules.
You also have the advantage of selecting your work in 'bite-sized' sections, to make loading the capsules easier. (Once you've shifted the work across though, you'll find it easier to work within the Hub format to edit and shift text elements around to accommodate non-text capsules.)
As a tip, once you've completed your Hub, you can easily save any changes you've made back to your own hard drive, by selecting the final copy from the published piece, and pasting it back in one cohesive unit.
Or, if you like, select 'print' from the panels below the piece, in 'edit' format, but when the dialog box pops up, choose 'make pdf' and save that back to your hard drive. Looks pretty good - and of course, no actual printing is involved.. Cheers.