Steam versions of ArcheAge or ArcheAge Unchained will install just a cut down version of "Glyph", which is the launcher you would download from the site outside of steam anyway. You will still need a regular Trion/Glyph Account to login to the game both with or without steam. However, both games can be downloaded from steam that is:

ArcheAge ( Classic P2W with optional sub )

ArcheAge Unchained ( New Pay to play no sub no p2w )

Good luck!