Right now, you have to click the Save button in the Drag and Drop builder and then go out to Library > Email Content and then locate the content again, then click the three dots, then select Create Campaign. It would be much more efficient to have an option directly within in the Drag and Drop builder to send a campaign using that very email. Perhaps add a Save & Send button?
(I've submitted this idea before, but I also think a button to Save & Close would be a super useful addition to the Drag and Drop builder as well.)