Haven't used that, but all I used was a Garmin HRM strap coupled iwth a UsbC-A adapter and ANT+ receiver that plugs into my phone. I used the EliteHRV app in Android.
It seemd OK but to be honest I felt it was rather gimicky and I cbf lying in bed for 5mins before I get up in the morning. Either I get out of bed and am feeling fit or not and train accordingly that day (or don't). Didn't really need an app to tell me that.