Hi Alex, not going to argue against your points at all b/c they all very valid. I WILL say in having worked with many clients using Planner Premium (formerly Project for the web), it's generally been a huge step up in functionality. It helps folks go from collaborative work into more structured project planning and management effectively. Once they see the difference in the two tools they get it, and can make a decision on one versus the other based upon their needs.
Sure Premium it's definitely missing some things that SHOULD be there, but for most folks see the value in the new tools. Example is calendars - in project planning calendars, while useful, get waaaaayy too cluttered with tasks, which is why the 'timeline' (or Gantt) view is extremely helpful in laying out all tasks on a visual timeline. Calendars are available in the MS Project Pro client today but honestly we don't find many formal PMs using these at all. But it would be nice feature to re-add in for the simpler schedules!
Def agree the AI component is a huge work in progress, as we're all trying to figure out the best use cases for this new tech!
If you look at Planner Premium today, Microsoft has added baselining capability (a HUGE ask for a long time!) so you can now do basic variance analysis. There's still stuff missing (actuals, anyone??) and I would agree with you that adding high value features makes alot of sense versus experimental stuff, but that's why these forums are great for both users like us and Microsoft to listen.