Well...
I'm not sure about this. I live outside China, yet watching seems just fine for me, so I'm not quite sure about how it is for other foreigners. o.o However I think for only watching a video you don't really need to know any Chinese. (Because a play button is a play button in any language.)
On another note. Bilibili videos can now be added to the song pages. The parameter is |bb_idX = (with X being the number 1-5).
Also as it is now, when the bb_id is added, no NND or YT link will appear. I'm not sure, how common it is, that BB singers also have a NND and/or YT account. If it is common, it would have to be changed.
Can you tell me maybe if this is common?
And also, the thumbnails of bilibili don't seem to follow any pattern that we can use. So instead, we'll have to display this *sigh* File:bilibili.png (Taken from VOCALOID wiki). However one can fill in the |alt_idX = parameter by putting in the yt_id with a decent thumbnail. It'll appear instead.