There was a reason that NASA was involved in fusion from the start: the space shuttle. Currently our ability to travel through the stars in limited by two things: one, our ability as humans to withstand zero gravity and two, our ability to fuel the vehicle. Fusion energy can recycle itself. Furthermore, hydrogen is the most plentiful element in the universe. It is estimated that a fusion powered shuttle could make it to Mars in 4 months.
By reducing the cost of propellant, fusion can enable space exploration and possibly even colonisation. Fusion will free up money needed for taking space travel to the next level.
A fusion rocket could theoretically be a lighter, faster vehicle that would accelerate through space much quicker. The issues of containment and the use of a magnetic field in space need much more investigation if a fusion rocket is going to make its way out of speculative fiction. Currently models seem to be leaning towards using fusion as a propellant as opposed to a fuel, so pushing the helium out the back of the rocket to push it through space. The idea of a self-refilling fuel is seen as a much bigger technical challenge.
What this does show is that fusion is the stuff of our futures. To invest in fusion now seems like a high risk with possibly only long term rewards. However, undoubtedly, these long term rewards will be very high indeed.