Yes, it is an efficient way to protect many outlets using a single GFCI. I found out the hard way that was the way it was wired. The GFCI outlet pair has a soft water system and a hot water recirculation pump plugged into it so I thought, okay - that makes sense (water things powered by 120VAC needed protection from accidental shocks). It never occurred to me that the other six outlets on that wall, 4 of them located 12' away, were also protected by that one GFCI. Besides a refrigerator plugged into that circuit, I have several security cameras and a DVR powered off that wall.
Early on in my ownership of the 3, I tried charging the car using the mobile connector from a quad outlet near the garage door. Plugged everything in and I thought the car started charging but when I came back out later, realized that it had stopped. Came to find out that when the GFCI tripped, it also cut power to the quad outlet. That took several minutes to figure out.