This is the best solution when you are building a whole system from scratch.
If you have to build a feature or whatever it is then it already got implicit permission from the jira sponsor or the product owner or whatever stakeholders are in charge.
And for a feature I don't have to lose days writing long documents.
I just think how it should work, I discuss it with the senior members of the team and with the stakeholders if needed.
From that point on I just speak with the users to understand exactly what they want showing them whatever I'm building to have an early feedback.
I think that is much more productive spending several days in a tight feedback cycle with your users than spending the same amount of times drafting the architecture in a document.
How do you get from "I just think how it should work" to "discuss it with the senior members"? You've got notes, at the very least, that you've jotted down about the proposed changes. Guess what: that's the draft of a design document! If you've taken any reasonably thoughtful approach you'll have just a little more work to make it formal, invite formal comments and feedback, etc. Not weeks "drafting an architecture" document, just days (or possibly hours, if it's a small change). That's a small price in time to pay for such a big dividend down the road.
