same ilvl - monk or dragoon

[GunsBlazing]

And a little bit more versatile too. They can Buff Physical DPS and Reduce Damage taken (5%) every 90s

I wouldn't say Machinist is more versatile.

Machinist can, as you said, buff physical DPS a bit and reduce the damage the party takes.

Bard, in turn, can buff magical DPS and also reduce the enemy's evasion by 10% with a 100% uptime. Rain of Death is critical if you have a scholar who actually DPSes well. It allows them to get a lot closer to the accuracy cap than they ever could, otherwise.

They're about equal in all fronts, they just contribute in different ways.