As you halfway go on to figure, I’d guess the idea is: if they show Tom Holland in the Spider-Man costume with the mask off and a little scar under his eye, people will say, oh, I guess he survives the movie that’s about to come out, maybe picking up a little scar under one eye in the process. And so you instead want to build the mystery and pretend that the latest Spider-Man movie has stakes and maybe he dies and anything can happen!!1!