You are welcome to use whatever definition of "small/medium/large" you like. Like you, 1-2 weeks is also far from the largest project I've worked on. I don't think that's particularly relevant to the point of my post.
The point that I'm trying to emphasize is that I've had success with it on projects of some scale, where you are implementing (e.g.) multiple related PRs in different services. I'm not just using it on very tightly scoped tasks like "implement this function".