My experience matches yours! For most of my work, building a quick animation in Keynote with the assets I already have is all I need. A robust animation or prototyping tool are overkill for quick storytelling or testing ideas.
That's not to say I don't think those other tools don't have a place, I just think they should come later in the process.
Question: Why do have to run the quicktime through GIF rocket and then place images into Flinto? Are you trying to recreate the animations in Flinto?
My experience matches yours! For most of my work, building a quick animation in Keynote with the assets I already have is all I need. A robust animation or prototyping tool are overkill for quick storytelling or testing ideas.
That's not to say I don't think those other tools don't have a place, I just think they should come later in the process.
Question: Why do have to run the quicktime through GIF rocket and then place images into Flinto? Are you trying to recreate the animations in Flinto?
And YES to Keynote files at a 90˚ angle.