The King Ring is the only way to use Honor of Orcs at present, but it is still worthless.
It levels slower and less powerfully than all but the cheapest of rings you can buy from the priest in the Level 10-20 town.
I got the King Ring on my account, and my wife had the Tie The Knot ring, which quickly outpaced my King Ring with our flower exchanges (the King Ring also gains experience from Flowers, but it levels more slowly with poorer benefits).
If you are going to buy a ring, buy the Forever Love ring. It costs about the same, and has really good power-ups. But even the cheap Tie The Knot ring is better than the King Ring.
At the last Orc event, I got myself another King Ring, because I thought I could load the Honor of Orc XP into it and Xfer that to my Forever Love Ring, but it won't even do that. Xfer only happens when you buy a new ring.
There is a bonus with the Red Wings, but I don't know anyone who is using that, and I don't know if the King Ring is involved. You have to kill more Orcs than your free daily allotment to get the bennies, so I think that is why it is also unpopular.
If you get a King Ring, it is a curiousity, but it won't help you much. Don't waste gold on it. And don't waste flowers leveling it up, unless you are going to buy a good ring later (you can Xfer the XP out of old rings when you buy new ones. Do the Xfer before you buy the Ring).
I would agree with your title premise of not buying it, but many of the other points are in error.
As I've stated elsewhere, the King's ring is the better singles ring. You are comparing to married rings.
Considering the Orc event lasts 7 days, and you have 30 free challenges per day, that yields a free-to-play score of 210. You just need to have both items equipped while killing to get the surppression points. A score of 210 is sufficiently more than the 200 required to get the combo-item title.