Just for the record, I haven’t done Instacart, and my most recent experience with DD was a little over two years ago so I’m unsure if it’s still done in the same way.
When I did DD it would pull up a map in the app to show me hotspots that were getting high volume of orders in the town/city I was in. I drove to those hot spots, and parked in one of the parking lots in the area until I received an order. It would give me a pop-up when an order was available for me that only said the location to pick the order up, distance I would drive, the pay for that order and ask if I wanted to accept it. Nobody was able to request me as a Dasher, the app would just ask me if I wanted an order. If I said no it went to the next Dasher to ask if they wanted it. I’m assuming that Instacart is the same way. I believe Instacart is done in a similar way but with groceries instead of food.
From my admittedly limited understanding if you wanted to help the community via Instacart and the alternatives, yes. You’ll get the occasional order while driving to a hotspot, but most of your time will be the spent the same way as it was with UberEats. Sitting in parking lots waiting for an order to pop-up.
If you’re not hurting for money, and you’re just looking to help I’ll always recommend reaching out to some of the local volunteer groups in your area. In my local area they’re almost always hurting for volunteers, and they’re always thankful when someone shows up