Also, let me add to this:
At level 20, a rogue might actually prefer having advantage over having two attacks sometimes.
Let's say you roll 17, and then 20.
The 17 hits.
Normally, you'd apply your 10d6 sneak attack then.
However, since you have advantage, you take the 20, your sneak attack crits and you do 20d6 sneak attack damage instead along with a 2d8+5.
Otherwise, you'd make two attacks, a 1d8+5 + 10d6, and then you crit on the second doing an extra +2d8.
Of course, the chance of this situation occuring is (19/20)*(1/20) for getting an extra 10d6 which is slim, whereas the rogue with an extra 1d8 every round they get an additional hit probably competes with that.
Even so, you're choosing between an additional tiny chance of getting super sneak attack or an extra 1d8, it's not a big deal.
You designate a creature within 5ft of the hand. THEN you can move it.
You can move the hand every time you do something with it, and while you could normally make it go pick up something, you can't even take the action in the first place if nothing is within 5ft of the hand.
You can easily move the hand into position on another turn since you can use it as a bonus action, there's no way that's useless.
And, as above, sometime advantage is better. And, what if:
a) you move first, visible but high initiative
b) you're not an assassin (you're an arcane trickster)
c) because of the above, you have neither advantage and there are no allies within 5ft of enemies?
