For fitness trackers, you're often going to get sensor files directly from a wearable device, but that device may have limited or even no interactive IO facilit

For fitness trackers, you're often going to get sensor files directly from a wearable device, but that device may have limited or even no interactive IO facilities, making it unsuitable for planning and analysis, which requires exporting to a more capable device. That device may very well just be your laptop, but you'd still want the ability to directly receive sensor data that your laptop can't collect because you can't hook your laptop up to a heartrate monitor and accelerometer and GPS while you're working out. For a recipe database, if you're thinking of something like a food logger, having the food database shared by all users instead of local to each user is what allows the data to already be there the first time you ever log that same food. If it has a barcode or simple description and anyone else has ever input the nutrition data associated with it, it's already available to you without every user having to input that data individually.