Wii Fit Body Check Channel may have got your information from various locations and uploaded it to a website according to this layout:
https://s.yimg.com/uu/api/res/1.2/vEenCP76Zhm_hM10W3doKA–~B/Zmk9ZmlsbDtoPTI5MTt3PTY3NTthcHBpZD15dGFjaHlvbg-
It also seemed to have collected information from the DS through the Personal Trainer: Walking game that I found used a pedometer accessory, also included in the layout.

The data uploaded to the web also contained BMI info from Wii fit. Health Professionals would review the information and send back suggestions and comments to the Wii (Judging by the layout it was in the form of a Wii Message Board letter).

It was developed by NEC, Hitachi, and Panasonic Medical Solutions (According to this website)

I'm really not sure about the rest of this. I'm still unsure about the “Insert the SD Card” screen shown in LunaValoaa's YT video. If any of you can or know someone who can translate Japanese, that would really help! I'll upload pictures of the Wii Fit Body Check Channel here so we can figure it out, but otherwise, I'm not sure what else to do. WiiLink24 has halted the revival progress of this channel, so it's kinda up to us to figure it out.

And yes, Wii de ultra hand looks quite boring, though I cannot get it to run on my Wii, so I can't really play it.