Depends. Are you a strong defensive player who really has the base that allows those changes to make a difference? Do you get attacked with tanks to snipe your town center often (common at high medals)? If neither apply, then even though that is quite good, it would make more sense to use your scarce supplies on an offensive or economic boost from a different artifact slot.
The way things are currently set up, it will be a long time before you are able to get enough supplies to take any artifacts to level 5, much less several. So prioritizing will matter.
-11% heavy cavalry damage would be almost worthless to me - I get hit by full armies, either mixed or Heavy Tank (which that wouldn't apply to). The attacker's tanks are just silo decoys, they don't do any significant percent of the overall damage. 6% reduced supply cart healing would be barely noticeable, and doesn't apply to Tactical Helicopters. The reduction to fighter damage and ranged siege damage would make a difference, but sounds like those are level 4&5, so a lot of supplies needed to even get to that.
So I would personally look at that artifact, wish it were in a different order, and then use it until I found something better in slot 1. I would never invest in upgrading it.