I disagree completely that its useless.
General:
I have used it countless times to summon the hand and push creatures off ledges and see them fall to their doom with fall damage and if at least knock them prone where my part is.
But that's the problem. It's not supposed to be able to do that at all. It's a cantrip, it's not supposed to be a one-shot kill or danger-free knock prone skill. It's a dinky little hand to carry very light objects and disarm traps while the no-expendable people are a safe distance away.
I have also used it on occasion when i was funneling and encounter through a door I placed the hand in the entrance so it something would be forced to use an action to kill it where my party was getting in position.
Also not supposed to be happening. The hand isn't supposed to be able to block enemies or be able to get killed.
As an Arcane Trickster:
The Hand is invisible so unless a creature can see invis you can scout entire camps without them noticing.
This probably also shouldn't be happening, because you should only be able to move it to places you can see. That's not too egregious, though, as long as it doesn't have a ridiculous roaming range.