> Having people assigned to tasks, a starting point, some initial steps to follow is something that increase delivery speed in the beginning a lot.
It's a balance of time spent planning against the value of the plan. Immediate-term "planning" is definitely valuable, IMO. Thinking through how some immediate work can be split up so that multiple people can make progress simultaneously, without stepping on each other's toes, that is definitely valuable. Having some discussion about what the next steps might be after those immediate steps are complete, that's also pretty much always valuable. Spending a small amount of time thinking about the next next steps can be valuable. But past that, in my experience, people often put more time into planning detailed steps than ends up being valuable. It's not that it has zero value, it's that it has a pretty high cost that, in my opinion, usually outweighs that value.
Also, just to note that I think spending time thinking about a "north star" vision of what a project is trying to achieve is also pretty much always strongly positive ROI.
It's time spent coming up with a detailed plan a few steps out from the immediate term that I find dubious. I don't mind other people spending that time if they want to, but I don't like spending my time in those planning meetings; I'd rather be getting to work on the immediate term tasks.