If you're on the newest build of EW 7, you can play youtube videos, although I wouldn't recommend doing it because of possible buffering and ads.
There is also the possibility of a video you're trying to play is copyrighted and youtube won't allow it to be played in a separate player like EW.
So, it kind of depends on what you mean by 'It wouldn't let me'.
It just said that the video was unavailable to play. I could watch it on my computer but it wouldn't play in EW. Probably because of copyrights. We don't do this often but we were in a pinch with no musicians. I did go old school very quickly though and showed the lyrics on screen and played the audio through the sound system. It's just that YouTube has some real nice worship lyric videos. We do have a Premium subscription. Are their lyric videos in the media store? That might have worked. Although that particular service was very themed based. Thanks for the training and info on FB last night. God's Peace!
I did a search and it looks like there is only one lyric video currently available in Premium. There are several available for separate purchase though.