You could make a game like Dreams no problem with blueprint. But if you want large generated landscapes, then you need C++.
Hi. I find myself in a position where I am curious about the limits of using Blueprints. I am curious if there is stuff you can’t do with blueprints and is only possible in c++. I know there are limits when it comes to multiplayer setup and stuff but what if i want to build a system for my game. Lets say I want to make a sculpting system similar to the one that the game Dreams has. Would it be possible to make that using only Blueprints, or is it only possible with using C++, or not possible in Unreal Engine 4 at all? Thank you.
Blueprints’ limitations depend on your goals. Sometimes it’s easier just to start prototyping with blueprints to understand what you’re missing 
You can also check the documentation, find classes you’re going to use and check how many methods have BlueprintCallable specifier