For a number of years, I've seen HEIF being promoted as a superior file format to JPEGs. A few different times I've shot it to play with the images (never on a job). The problem I see is, you can't actually use the files natively and only a handful of programs can either view them or work with them. Additionally, you really need to convert them to JPEGs (or TIFFs) in order for them to be used in any worthwhile way. I shoot primarily RAW (for myself) or RAW+JPEG on jobs so clients can edit quickly through the JPEGs. (Most are too lazy to use RAW if I'm not doing the conversions for them.)
So, again, what good is the format? Will it be another dead format not far down the road? Does anyone use these files on a regular basis, and if so, how?