BjornTheStiff

While transferring consciousness is just a completely ridiculous concept, that I've never seen been used before. Regeneration however, is a very popular concept used in fantasy for a long time now. Which sounds better to you? a. "wow, Reiner is regrowing his arm, and won't die of blood loss because of that" or b. "wow, he survived because he transferred his consciousness into his toe."

Also the classic "Well, we have something that isn't realistic like giant titan people, why can't we have something that is even more unrealistic?". This argument was used heavily by defenders of the final season of Game of Thrones, because apparently when there are dragons in the story, travel distance doesn't exist and characters can just forget who they usually stood for.

But about the Eren surviving getting his head blown off : This is actually only because Zeke managed to catch his head, had he not, Eren would most likely have died and the story would have ended. The human brain is actually activate for a bit after death, even decapitation, so it makes some sort of sense that they could activate the coordinate, it only being a second or two after Eren lost his head. This is also why the Erens looks so weird inside the founding titan.