Long story short: I already have the Tabard of the Lightbringer saved in my T-Mog wardrobe by my warrior and I have an unused one on my paladin but debating if I want to keep it for that added cosmetic or just sell it? So I’d like some thoughts on this.
Note: you can T-Mog another Tabard to look like the Tabard of the Lighterbring but it can’t do that 5 minute light show the real one actually does.
keep it! the light show is cool.
Tis your item, you do what you think is the most fun! Sell it if the gold sounds good or keep it for a character that will use the on use effect. Whatever makes you happier. 
I had mine in my bags for months and never even thought about equipping it once
Ended up selling it, and somehow have the appearance unlocked for transmog
I really should finish that legendary one of these days. Now if I could only find someone to help me with Lanathel oh well.
Thank you for the comments, I’ve chosen to keep it. I remember the Blood Infusion quest in my paladins quest log for years and it felt right to keep it and besides its a paladin I have to at least have one using it. Thank you again everyone.