I do this myself (albeit pretty rarely) since the rear camera is significantly better than the front camera, especially in low light.

Your comment led me to the Insta360 device that makes it easy to take selfies with the main camera:

https://www.theverge.com/tech/907670/insta360-snap-usb-c-mag...

Second screen: provided by USB-C screencast and accessibility settings for to support touch. Image of device: https://platform.theverge.com/wp-content/uploads/sites/2/202...

My first phone that had a (rear) camera 20 years ago also had a chrome-plated mirror thing to help us take selfies. I guess nobody called them selfies then.

I guess point and shoot cameras also had those mirrors back then.

Glad to know that kids rediscovered camera selfies.