Ask HN: How do you visualize your product roadmap?

I have a question: I've been working on a product for product management tool for a little while now. Among other features we offer product roadmaps with different views of the roadmap:

- a simple quarterly "card" view: basically saying we do these things in this calendar quarter, and those things in the quarter after that, etc.

- a Gantt view where you can really map out how long you think things will take for each item on the roadmap (in number of sprints)

What really puzzles me here: I find the simple quarterly card view much better, more pragmatic, and also less overhead (as a user). Yet most people seem to be using the Gantt view, and we get many more requests for features on the Gantt view.

I am really wondering why this is. Any ideas? For example, does it really matter to plan out how long each item takes, or isn’t it enough "this feature will be shipped in Q2, and this in Q3 or later"?

And which type(s) of product roadmaps do you prefer?

p.s. the tool I am working on is here if you want to have a look: https://www.getshipit.com