Has anyone used a camera with phone app to check on loved one when out?

My mom bought a baby monitor for my dad and the CGs while she was in rehab.

Yes all the time. My husband was completely bedridden in our living room, for the last 22 months of his life, and it was just he and I here for the most part, so I invested in some fairly inexpensive Blink cameras, that I could easily access from my phone, either overnight to check on him without getting out of bed, or to check on him when I had to run an errand or was out to lunch with a friend, etc. I was never gone for long, but as all caregivers know, it's important to get breaks when you can. My cameras are the older models where I can just hear what's going on, but they now make them with 2 way talk which is even better.
My husband was always so sweet when he would hear the camera click on, he would smile and wave at the camera, because he knew that I was checking on him.