Honest question about language: why say "killed/dead" when you only knocked someone?

This might seem nitpicky or trivial, but please hear me out. I've noticed that a lot of pros and streamers will say "I killed one" or "[character] dead" in their comms to teammates when they've only knocked somebody down, and I find it confusing.

We all know that knocked and dead are two distinctly different states in this game. An enemy that is knocked could become un-knocked very quickly by a Lifeline teammate, a self-revive, or another teammate taking advantage of a third-party distraction.

When a teammate says they've knocked somebody, I take a mental note to know I either need to keep track of them while I find the rest of the team, or it might be the right time to thirst/finish them. On the other hand, when a teammate says someone is dead, I know they're truly no longer a problem. At least, that's what I think I should be able to know. If a teammate told me someone was dead, but then that "dead" enemy suddenly re-entered the fight when I wasn't expecting it, I'd be frustrated about receiving bad data from my team.

Saying killed/dead doesn't even save time, as it's the same amount of syllables to say in a heated moment.

Am I overthinking this? Or is there a valid reason to make knocked and dead synonymous terms? Thanks for your input.