Yeah, MMD stuff isn't really my thing but every once in a while I find jewels like that video.
I think that it would be better animated because we know when people animate it with actual pictures and not models we know that they put more effort. MMD is a free cheap program; but I don't complain since it recently got better, and I can't lie that VOCALOIDs are my childhood friends.
Hm, if you ask me, it's a passing fad; and that it's become somewhat like a meme where people would make it seem funnier by putting in characters from certain fandoms. Put Batman and Superman there, it's gonna be/look funny because it's ridiculous.
That's why she spends most of her time on the river and away from Shieiki. She already catches slack for being so well endowed. But all Shieiki needs is a little love. She'd loosen up if Komachi spent a passionate night with her she'd be a little less uptight. I doubt it would effect her judgements as a Yama though.
That's probably why it it's Youmu. Youmu's easier to talk into things.
But is Shiki even aware that she needs a good one night with Komachi? I never saw it that way though; I'd always imagine Shiki would be too much of a workaholic to notice these sort of things and Komachi would've somewhat given up on trying to stick around her boss for too long...