I suppose, to keep the cost of it’s devices down, neither Motorola’s Moto nor Google’s Pixel smartphones have a Photo Gallery app.
Both rely on Goggle Photos, a Cloud service, to display your photos and videos.
Google Photos works well to display your photos and videos stored in your Cloud space – as long as you have Internet service. If you are out in the boonies with spotty Cellular service and no WiFi, you have no access to your favorite pet photos.
Personally I’d feel a bit deprived if I did not have an app to view and work with the photos and videos stored in my smartphone.
There is a workaround by going to the Play Store and download a third-party photo gallery app.
The Android Police website has done a solid review of eight Android photo gallery apps that will meet a variety of different needs and skill levels.