Realistically, you can't ask Verizon questions and expect "right" answers.
It's kind of like asking a car dealer how the internal components of the V8 engine work.
They just deal em, they don't make/service them past a certain extent.
Now, this is just in MY OWN personal experience:
I used to use them, But I found myself checking it all the time to make sure it was killing tasks, working properly, etc. Secondly, when i decided to stop using them (thanks to this article:
FAQ: Why You Shouldn’t Be Using a Task Killer with Android), I was pleasantly surprised how much more stable, smoother and longer my phone was running.
When you kill processes, sure it makes things faster for a second or two, but those processes are re-started the next time you want them and that takes more battery power/memory than just leaving them running. Plus, Android actively kills tasks on it's own when it needs memory or a task has been inactive for a while.
So, IMO, no, you don't need them.