You can draw transition animations if you want to.
No, you cannot draw a smooth transition from ALL animations to each other
True, but in this day and age it pretty much doesn´t matter
This has another more important meaning - if a sprite contains a large number of animation frames (it occupies a large amount of memory, respectively), then a delay may occur during its creation (the microlag of the entire game). Therefore, you need to upload such sprites before they are created.
And since because you said it cannot be done with the same quality in Construct... observe:
I saw this game. Good example. But not quite what I meant
And I think it’s not quite right to say so - "You can do it, just draw." Not only will this add problems to the game and so it will take even more time to implement and require great drawing skills. Not every developer has it. Therefore came up with special programs that enhance the quality of games and simplify their creation. They support a large number of engines, but not C3.