Overview:
    USB audio (UAC2): 4-ch capture to host over high-speed USB, stereo playback for headphones.
    Standalone recording: 24-bit WAV to SD: 4-ch@48kHz or 2-ch@192kHz, with optional WXYZ encoding.
    Standalone playback: file browser + player from SD, with APO-format EQ.
    Live monitor: ambisonic (A-format) to binaural decoding
    USB mass storage (MSC): Switch to SD mode to download the files from the Device.
    UI: 1.54" E-INK display with intuitive(ish) controls

Why?
Look up the price of a 4-channel USB interface… Go on… want with similar specs…? £222 ? Works for you? No…?

For about £40. If you can make it, it is the cheapest thing in it’s class by a