Most modern computers can do about 30/h a second. Coinhive currently pays out 0.00009030 XMR ($0.02 USD) per 1M hashes.
For a 10 second pause, they'd mine 300 hashes (about $0.000006 USD). To make $1 USD, they'd need to have ~166,666.66 people connect to their in store WIFI.
My fully maxed out 2017 rMBP can only do 50-60h/s at full speed with all threads. Most people don't have a machine nearly as powerful as mine.