If you have access underneath to reinforce, I can't think of any reason not to. It's not expensive and not difficult.
OTOH, I have thought about a form of reinforcement above the floor. What if you were to build a platform with a lot of 2x4s on end with a sheet or two of good plywood over and under them, with dimensions larger than the tank? It could distribute the load over a larger area. Just a thought.