Thanks! Author here. I believe that's the key takeaway, knowing your audience and being able to do things that are perhaps controversial. In our case, it's also focusing on our strength while we are such a small team. Being mostly backend devs (although many of us launched products where we did the full stack) CLI is in our DNA.
We believe if the product and experience is not compelling enough, having a shiny GUI won't help. Then why waste the effort instead of making our core proposition stellar?