Steve Calde of Cooper, a design firm making the argument for removing constraints and exploring:

Typically, the output of this design exploration is a collection of hand-drawn sketches that target key plot points in the most important scenarios, and signature interactions (parts of the system fundamental to the experience). The sketches often explore a range of ideas, some that can be implemented within all known constraints, but also others which may bend (or break) constraints. After that, it’s really a business decision our clients need to make about how to proceed. Sometimes it makes sense to restructure deadlines, add resource, buy a technology, or abandon a legacy infrastructure to get that “killer app.” Other times it doesn’t make sense…but as designers it’s our job to imagine the future and enable business decision makers to make the most informed decision they can.

This is the bridge between concept videos and the iPhone. It’s putting pen to paper and figuring out what that tangible product is and how it can work. It imposes some real-world constraints, but Calde is arguing to remove the self-imposed constraints because often times those are arbitrary and not grounded in what the true goals are.

If the goal is to build a great product, you’d take one path. If the goal is to hit a deadline or meet a certain cost, you’ll take another. It doesn’t mean that eventually the constraints would be reintroduced and you’d have to prioritize, but define your goals and at least explore your options before imposing them.