I live in silicon valley where all these new delivery services are being tested, and I almost never go to the store. Google Shopping Express delivers non-perishable groceries to my home within 24 hours, Instacart delivers fresh groceries within 2 hours, and Amazon delivers everything else I need within 2 days. I really want to sign up for Amazon Fresh because they deliver perishables and everything else same day, but it's a little pricey.
I hate going to the store now (especially since our local market isn't very nice - I love a good market). For me it is a big chore. I work from home so I'm rarely even "driving by" the market.
Amazon, google, and others want to enable a world where no one goes to the store (and we all order from them). It's nice not having to go to the store. Your cute calculation of 4.3 minutes saved is making assumptions that totally don't apply to people like me. I don't want to take a 30 minute experience and shave ten seconds off, I want to eliminate the trips to the store entirely.
It's fine if you don't see the need for new products, but just because you don't see the need doesn't mean there isn't one. Not saying this product has a need (I feel like I can use my smartphone) but you've completely missed the big picture of deliveries for everything. In San Francisco you can get a bento box delivered in 15 minutes for $12, and I just got a flyer for dinners delivered starting at $8.
Everyone wants to do deliveries, and once they're done by robot it will be so cheap we'll all have it.