I've never bought it. It will still involve being able to transfer information FTL, and then you're on to the Grandfather Paradox. On top of it, let's handwav

I've never bought it. It will still involve being able to transfer information FTL, and then you're on to the Grandfather Paradox. On top of it, let's handwave all of this away, poof. Any aliens anywhere in the Universe would also be using it once their technology got to that level. Just from the lack of visitors, we have three possibilities that are immediately evident: 1) Humans are among the first intelligent species to get to this technology in the entire Universe. 2) Other species have it, but all of them, every last far-flung one of them, even the renegade civilizations or the mad scientists at the individual level, abide by not using it around humans. Despite all of their numerous reasoning capacities and utterly inhuman motivations, every last sophont with access to the tech has agreed upon this, and has for thousands of years. 3) That tech can't exist. The first and second are unlikely, statistically.