The Summoner AF3 armor uses it too. Or at least, they paint arcane geometries on their skin for various reasons... Here's some of the stuff from Lore Book 2.

Quote Originally Posted by Summoner Form & Function
Aside from the horn, summoner garments resemble those of other mages, lengthy and seeping--though they are unique in leaving some portions of skin uncovered. Y'mhitra of the Sons of Saint Coinach asserts that this preference is in fact practical, enabling the summoner to better absorb the essences of the primals he confronts. And while gaps in the one's raiments do reduce overall defense, it could be argued those who dedicate themselves to harnessing primals' power for their own are not, at any rate, innately inclined to an excess of caution.
Yes, you read that right. Summoners don't like having a lot of "stuff" between them and the ather they absorb when they kill primals so they purposely fight half naked. And if that doesn't make sense, killing a primal to use its powers is a huge risk as it is. What's one more? Or, summoners are probably half-crazy already. If they were saner, they wouldn't be summoners. And would use conventional mage robes.

Quote Originally Posted by Channeler's Vest
This daring vest protects only the heart, leaving the upper arms and stomach exposed. The dearth of fabric makes it impossible to stitch arcane geometries as one might on a robe, so the arcanist compensates by painting one on his skin directly.
So you don't have to go so far as using aetheric ink in tattoos for it to work. Using it like normal body paint works just fine.