They have the Ranged keyword and the early ones are terrible Synergy with other traits
Leadership and Tactics, no real synergy with either sphere though. This was the case until the ninth cycle gave us a new Archer ally, which was more meant as a joke towards the community. As of this moment, the Archer trait remains undeveloped outside the Core Set. The two Ranged allies in the Core Set both got this trait, with the hope that the trait might get developed in future cycles.
The only reason that this trait got revived close to the end of the ninth cycle, was as an inside joke to the community, as the Hobbit Archer has the same title as his traits. The other Archer trait cards are not worth the deckspace, let along the resources that they cost.
There have been only 3 cards with the printer Archer keyword, and only one is worth including in your decks. The Archer trait was first introduced in the Core Set and has proven to be one of those traits that got abandoned by the developers right after.