This treatment is extraordinary, but in a slightly different way than it's usually indicated. It'll likely remain a niche treatment, but what is interesting about it that it's one of the first instances of manipulating human cells outside the body and re-inserting them. Not quite genetic engineering (as far as I understood, they're inserting a molecule, not code to make the cell produce it), but pretty close. It is, of course, great to have as a last resort blood cancer treatment, but to me, the real deal is that it may pave the way for further treatments in that vein, perhaps even including actual genetic engineering. Ultimately, I feel that this is the only way we're going to really "cure" some diseases, including most cancers.
Also, we should remember that most likely, there will never be such a thing as a single "cancer cure" (other than something equally broad, like "gene therapy"). Cancer is not a disease, but a family of diseases. Blood cancer is only tangentially related to things such as brain tumors, lung or breast cancer. Even lumping the various kinds of tumors together is a mistake, though they share more similarities.