I prefer the human checkout and it's not for any of those reasons.
For one thing I have a family of 5 and scanning that many groceries at a self checkout is super painful.
Next the grocery store made its money off of the backs of their workers then when it wasn't convenient anymore they fired a bunch of them and replaced them with machines. Now you have 2 humans in the front of the store doing the job of 10. Their only motivation for adding them was money and not convenience based on how it's been implemented. I still have to wait in a huge line that wouldn't be there if they had cashiers and machines together.
I love the idea of them it's just not being implemented in the right way to make it super helpful for the customer.