I have, and it was actually wonderful. It's enormously easier to just walk in, grab what you want, and walk out, without having to be gated by a checkout system whether it's manned or unmanned. I imagine they're banking on the idea that it's psychologically easier to just walk in for a single item and not feel like you have to make the trip "worth it". It was also a much better organized store than any in the area, which I presume is basically required for the tracking to work. This results in a complete lack of lines. Also, during the earlier days of the pandemic when people didn't know much about how it spread, I appreciated that I literally never had to touch anything other than the food I was literally buying: no doors, no credit card reader, nothing. The only sort of gating is that upon entering you kind of have to hover your palm above the device (there's an alternate mode where you use a credit card).
The only downside is that it is smaller than my regular traditional grocery stores, and while it makes up for that somewhat by better organization and presumably better logistics that let it restock just in time so it doesn't need huge amounts of spare space, it's just still not got the same selection. So my pattern became little shopping trips there, big (or very specific) shopping trips at the larger stores.
I can't stress enough how much easier it is to just walk in, grab something, and walk out, without having to handle anything. You can still see and cross-check the bill on your Amazon account. I double-checked more carefully than I do when a human is scanning things, but it was always right.
It's unfortunately been closed for over a year now.
Yes, you will be tracked in the same sense as you're tracked if you buy stuff at Amazon, who knows your address already. And I don't relate at all to wanting to use cash, that's a hassle. I appreciate the privacy difference, but I don't really care if a bank can tell that I buy groceries at an address close to my house. I'm not trying to diminish your concerns, but I think you're well outside the norm.