The device is popular because it is cheap (often under $50 on AliExpress or eBay) and features a full-color TFT display, an encoder knob for tuning, and a built-in battery. However, the "firmware" is the soul of the radio. Without good firmware, the ATS-20 is just a collection of chips and a screen.
: Access to the LW band (153–520 KHz) and the full SW range up to 30 MHz. Ats-20- Firmware
Community developers often redesign the UI completely. This can include better contrast, waterfall displays (showing signal history over time), and more intuitive menu navigation compared to the stark, industrial interfaces of factory firmware. The device is popular because it is cheap