If the only intent of the invocation is to push away creatures that are close to you it seems to make it a much weaker addition since youd only be able to use it at a disadvantage
I think where we're getting hung up though is on the wording. "You push the creature up to ten feet away from you". I totally understand where he's coming from. It could mean that the push only afffects a creature that is up to 10' away from you or it could mean that it pushes a creature...
My dm has ruled that repelling blast pushes a creature up to 10 feet away from you a distance of up to 10 feet. I read the description as meaning any target of my eldritch blast (within range of my cantrip) gets pushed 10 feet away when it hits. Am I reading this incorrectly?
Combine it with mass suggestion though, and have fun.
Cast Demiplane on wall and open door... Cast Mass Suggestion on angry mob.
"Suggest to angry mob that they hide in here where it's safe, before this turns into an all-out bloody battle."
Close door, and go enjoy a nice pint at the bar.