I find in the first case, I can be much faster when I can just think. Instead of having to switch mental contexts between "What's my logical process" and "How does that translate specifically into this language/framework/whatever." A simple example is if I want to iterate through every item in a container, I'd like to just type 'for', tab, the first few letters of the container variable, tab, and have it all set up. Resharper does this, and will even name things appropriately for you (if the container is something like myInts or intList, it will name the item myInt).
I used to do most of my planning on paper, or in a text file for this reason. But it's much nicer to be able to merge planning and coding as early as possible.
In your second case, well (1), maybe this is true for you and others. But not for everyone, myself included. I have a pretty poor memory for specifics. Is it myList.length(), myList.length, myList.Count, len(myList), count(myList)? On top of this, every one of the previous examples is valid in a language or framework I use at least on a weekly basis, if not daily. I may be doing python and javascript all day at work, then go home to work on a game in C++. It leads to a lot of confusion. (And about 30 minutes until I remember I need to use brackets and double quotes again, haha).
Everyone has their own ideal purpose of an IDE, and JetBrain's goals are pretty much in line with what I want. I agree that many of the fancy features they show off are just getting around the short-comings of C++. But to me, that is the point. I like the IDE to remove the actual "coding" aspect as much as possible. Allow me to think through the logic and control flow. Not whether the current item has to be dereferenced or not. Let me think of the actual data structure, and not whether it needs to be called .push_back() or .append() or .add().