Seed will always look better than WuE on any fight.
WuE is ONLY good on hard hitting bosses or where your HP is lowered like Tyrant. It basically has 0 use outside Tyrant and Mythic Manno(maybe, im using it cuz of our strat).
Seed is really only good if you have a constant DoT or there is constant AoE damage that sends it back to the boss and obviously the lower the damage per hit the strong Seed is since its not like WuE and will absorb up to 90% of a hit.
Problem is a lot of people just look at the meter and be like "damn that did a lot of healing" without looking at if it was meaninful. If it did a fuck load(like it does on council dia tanking) it actually does good damage too, but most bosses that isn't the case.
Seed if you do doomfire on Mythic Archi is actually really good along with using it on Council. HFA I guess if your raids dps is bad. My guild has a average of like 75-80% active time on that boss cuz there is nothing alive. So I don't even try anymore on it.