I was just in Seattle last week for a conference. I walked past the Amazon Go store on 7th Ave. From the outside, it looks like an ordinary city grocery store.
I wouldn't recommend a one day trip from San Francisco to Seattle, especially not for Amazon Go. The flight from San Francisco to Seattle is 2 hours 10 minutes. The cab ride from the Seattle airport to downtown is 30 minutes (one way). Plus the Transportation Security Administration recommends that you arrive at the airport 90 minutes early for domestic flights. If you arrive too late, you won't have time to go through security and get to your flight.
So... you would need to travel 4 h 20 min (flight) + 1 hr (taxi round-trip) + 3 hrs at the airport (getting through security). That's 8+ hours of travel to visit a store that looks like an ordinary grocery store.
San Francisco is a beautiful city with lots of history and interesting sites to visit. You could probably find many interesting things to do in SF for a day.