I get that, that’s what I do with my team, but I’ve never heard that referred to as “doing Kanban”. Maybe I’m just being pedantic, but writing an article to say “you don’t need Scrum, just pull tasks off the board” completely misses the point of why teams use Scrum.
Scrum is pushing stuff into a sprint. Kanban is pulling the highest priority stuff through - it's done when it's done.
Metrics/Analytics can be calculated when your done based on actual information, as opposed to the beginning when you're guessing, and likely to be held to your estimates.
For us, visibility isn’t an issue. I would say estimations are by far the biggest struggle we have in “doing Kanban”. Luckily, they’re not super important for us and I usually bubble up a very rough estimate in monthly reports to management, but in an org where they matter more, I can absolutely see why Scrum gets adopted the way it does.
Why do you estimate when using a kanban? You might look at an item and break it down for simplicity. You also might go in with a goal of 'one card per member per day' or something similar. But nothing should be fixed to an estimate. If something is delayed, it should show up stuck in a lane. Respond as needed.
Because work is deadline driven by whoever is paying the teams' salaries. If you can't accurately estimate when you can get it done, you break it down until you can you get replaced by someone who can.
