Their heart’s in the right place. They’re trying to preserve detail in the image despite the downscale. People doing encoding like that are usually thinking only of PC playback when it comes to choices.
Edit: A questionable pursuit of you’re going to bit starve the video to begin with. You’re already aiming for a mini-encode, no reason to fret over chroma subsampling.
Edit2: Just looked at the mediainfo on that again – 53% audio? Yikes!
Likely just copied over the original audio from the disc considering the 448 Kbps AC3. Poor use of limited space here since AC3 is a constant bitrate codec. I would have transcoded that to a VBR AAC of like 160 kbps, and thrown the saved bandwidth to the video side if I was aiming for a final size in this range.