Saying “we charge markups, but we won’t tell you what they are” is still not sufficiently transparent, in my opinion. Yes, Amazon and grocery stores do the same thing (at face value, anyway) by not disclosing their COGS. But the key difference is that my next-best alternative to Instacart is to just go to the grocery store myself. My next-best alternative to getting something delivered from Amazon isn’t to get it more cheaply from a brick-and-mortar Amazon store, or to buy it directly from their suppliers - it’s to get it from a different retailer entirely, and I can trivially compare all-in prices between other retailers and Amazon. So I can easily assess whether it makes sense from a cost/benefit perspective to buy something on Amazon, but I can’t make the same assessment for Instacart.
I do think the service creates value. But I still hope that, at the very least, it soon faces enough competition that it’s at least forced to be fully transparent about the cost of its service. I want to see one number - the difference between what an order of groceries costs me on Instacart all-in, and what it would cost me to go to the grocery store and purchase the same items myself. As long as I can’t trivially find or calculate that number, I won’t use Instacart again.