True. But to be fair, the decision by creators for humans to still use solid projectiles is more of a thematic choice. The original trilogy was supposed to be something like a "Space jungle Vietnam". I guess it would break that idea if they used something else. Tech seems very inconsistent in lore. You can say, "They still use bullets," as much as you want but that's ignoring things like the slipspace drive, cryo, massive interstellar warships, cloning, mapping human brain to AI, etc. Cutting it down to something like using bullets or other familiar, current weapons, for thematic purposes, just seems like an underestimation of their technology especially once actually utilizing and adopting the Forerunner tech later on.

It is absolutely within the realm of reason to think that the technology could exist in the context of human tech in lore.

And there was "juice." It was in survival mode focusing on just keeping the wearer alive (whatever it means by that exactly is up for debate because it's pretty ambiguous) until he could be retrieved. It's like when my phone is dying and it's like, "Cool you can do some stuff. Battery at 15%. Dimming front light. No photos."

Anyways. This is what zero Cortana foots does to a mf