What is Always On mode?
Always On means that the output of the battery or power bank does not shut off after a set amount of time. There is no low current shutoff. It stays on.
Most battery packs shut off when there is no current draw. However, there are times when you want to prevent the battery or power bank from shutting off when there is little to no power draw. With an Always On battery, you could power IoT devices sensors, GPS tracking devices, perform time-lapse photography with GoPro and other cameras, or run Arduinos and Raspberry Pis and their peripherals.
If you want to power a device over several days, weeks, or months without human intervention, then the Always On Mode is a good fit