That big decrease in cost allows the company to capture more market with a lower price, increasing profit. The profit goes to repay the investors that up-fronted the money to develop this. But the savings in everybody else's pockets eventually boost the economy, creating jobs.
Software can be write once, run everywhere. You could replace thousands of cashiers with software written by a team of 10 software engineers.
Maintenance of hardware/software could be taken care of by a few people running to multiple stores throughout the day. Example would be Starbucks in San Francisco. There is a Starbucks nearly every block in the inner-city. You could just have two guys walk from store to store to perform checks/maintenance.
So yes, I see big possibility of thousands of service workers being out a of a job due to automation. Which is why a lot of people are saying we need to seriously consider something like universal basic income for the near future ..