It's pointless. Bumping a thread puts it back at the top of the subscribed threads, the same place it resides when you first post. Bumping right after you post a thread is completely redundant.
You're wrong. I've noticed a bumped thread when I wasn't pinged to it. Then I've "pinged" it to a list of friends if I thought they might be interested.
I guess you're just in a mood to argue with people today. I took the bait. I normally don't bite, and I'm sorry to see I did so in this situation. I have bigger fish to fry, so see ya later.
But not necessarily useless. I typically ping or bump a thread I post immediately after I post it so that it shows up in My Comments (otherwise, I have to wait until someone else posts to it to see it there).