Yes, i downloaded the app yesterday from Google play store so that I can share and read books etc with my 5 year old DGS whilst my dil helps my DGD with homeschooling. I think you can use it about 15 times for free and you then have to pay. It will give me the opportunity to see whether it works for us. I haven't tried it yet, but plan to do so on Monday. It was simple to download and set up and there are other activities to share.
Caribu is more than just a video call. There is a library of books to select from and you and the child view and read the same book each from your own device. At the same time, the child can see and hear you as you read the book to them and you can see them and interact with them. It's like physically being sat with your child and reading the book together. As well as reading books together, there are other games and activities to play with each other.