If for some reason, you are unable to do your own shopping, this is an acceptable alternative. But the experience varies so much based on which shopper is randomly assigned. When an item is sold out, sone people have no common sense as to how to replace it. I’m a vegetarian, and Tokfurky Italian Vegan Sausages are often out of stock, and more than one shopper has tried to replace it with pork. And shoppers have sometimes shown up as much as an hour earlier than your scheduled time! What if someone is not home, or showering, etc? Being too early is just as bad as being too late. And when there is a 1 hour delivery window, it shouldn’t be an issue at all.
Also, you basically have to be available to approve/reject changes and live chat with shoppers in order to get what you want. So this options doesn’t work if you are actually busy and not, say, homesick. The general UX is bad too. When something is out of stock, you’re only allowed to choose from 2 possible replacements that often don’t make sense.
I basically use this when I am home sick, or in the middle of a project but still can check my phone often. If you can’t be right next to your phone during every order, avoid Instacart. I’m just using it until something better comes along. I like that I can shop at my local store, where I know the general stock and pricing. That’s the only thing that makes this better than Peapod or Fresh Direct.