Please provide the Inbox/Inbox Pro as a PWA standalone app mainly for the use of smartphones.
With the addition of Google Q&A, Live Chat, SMS and others, this unified inbox will need to be monitored at all times.
However, customers are not always in the business app on a computer. The current business app is not at all mobile ready and therefor unhandy.
In order to drive user acceptance and adoption a standalone PWA inbox would be very beneficial.