Still planned, but plant gameplay needs to enter the strategy mode much earlier, otherwise it’ll be super boring. So while it is still planned, that’s way off the intended path to finish the game so it isn’t any kind of priority to get done.
I think pushing the button is much better, because you actually need to bind with other cells. If you just had a part, you can rush to get that part and become multicellular. Now instead you actually need to use the binding agents which is a part required to reach the multicellular stage. Instead of just slapping on a bunch of parts while quickly speedrunning through generations.