Yes, but the fuel is also the reaction mass for the rocket engines. You can replace the fuel with something without a lot of chemical potential energy, replacing that with the energy extracted from the total energy conversion of that two grams of water, but you still need to have a lot of spare mass to throw out the back to make the rocket go.
Unless, of course, you’re planning to launch the shuttle from some kind of slingshot. 
Hm - speaking of slingshots… I always wonder why the rockets are launched from standstill. Wouldn’t it make sense to give the rocket the initial boost from something like a giant railgun?
Doing it for a vertical takeoff would probably be impossible, but an angled one could be done. Wouldn’t that save a significant amount of reaction mass and increase payloads?
An angled launch trajectory means you have to go through more atmosphere, which is bad news. You could straighten out to near vertical right at the end of your launching rail, but that would also cost you. And you’ve also got a lot of complicated infrastructure that would cost money to set up, and would be potentially subject to a variety of failures. I’m sure that NASA considered it, but rejected it in favor of less expensive methods.
EDIT: Oh, and as for reaction mass, that won’t be the same for all launch methods. You could get away with less reaction mass, if you throw it out the back quicker. I don’t know exactly by how much, but I’m sure you could get a significantly more efficient launch overall if you had some fuel that would annihilate completely, even if you did still need reaction mass on top of that.
I still don’t get it. How is the mass of the system of two gamma photons still be the “rest mass”? Isn’t the whole point that you can’t measure the photons at rest?
And, anyways, what does no longer referring to rest mass accomplish? In other words, where is the rest mass concept deficient to the point where it has to be replaced? Is it just that the mass isn’t always at “rest”?
BTW, it sure wasn’t obsolete six years ago. What changed?
Orbital velocity is somewhere in excess of 17,400 MPH. It would take a very large machine - and destructively large accelerations - to impart any meaningful initial velocity before the onboard rocket engines take over. Rather than build a long, complicated slingshot, it’s easier just to put more fuel in the vehicle and let the engines run a bit longer.
However, there is a free boost that’s available without any slingshot required. Ever wondered why NASA usually launches its rockets from Florida instead of Maine? 
Photons do not have rest mass, but they do have momentum. So you can imagine a frame in which the sum of the momenta of several photons is zero (e.g. if two photons of the same frequency are traveling in exactly opposite directions.) This is the rest frame of the system of photons. The photons are, of course, traveling at the speed of light, but the average of the system is at rest.
Chronos’ point is that even though the photons themselves have no rest mass, the system, in the rest frame, does.
I believe it is relativistic mass (i.e. the one that gets bigger as velocity increases) that is deprecated. Mostly because it is based on a Newtonian expectation carrying over to relativity. In Newtonian mechanics, if you thwack a particle with the same impulse over and over again it gets incrementally faster each time. In relativistic mechanics it doesn’t, which is exactly what would happen in Newtonian mechanics if the particle got more magically more massive as it got faster. But that’s just a crutch to maintain the validity of Newtonian intuition, not an actual worthwhile concept.
The concept of rest mass is not considered deficient: It’s just gotten re-named to the simpler word “mass”. If you choose to continue to use the term “rest mass”, your only punishment is that you’re going to the work to say an unnecessary syllable.