The opportunities are huge. Anytime retailers or other service providers can create an easy communications channel to their shoppers, its a good thing.
I think the barrier to widescale adoption so far has been the need for iBeacons to communicate with an app on users' phones. People don't want to download another app if they don't really know what it will do for them. A number of retailers will have their own branded apps on which they could add beacon support - but again, users have to turn them on when they go into stores.
With the introduction of Eddystone beacons and Google Nearby all that is going to change. Google has created an environment where you do not need to download an app to receive a beacon alert. Its still early going and I'm concerned that there will be a bit of a learning curve for users. But the technology will open up all sorts of opportunities.
We're building a tool with this new technology to aid retailers in managing and tracking customer experience. If you want to discuss, we can take this off line
Here's an interesting resource to get a handle on the market opportunity for beacons in retail - they have a publication specifically targeted to the retail industry https://www.proxbook.com/