I don't have all the details of their Template in mind right now, so I won't dive into the many ways of controlling or avoiding undead that 3.5 is full of. I'd appreciate a link to the Template, if I'm wrong about this.
These undead don't rampage at the drop of a hat, but they're still undead. When a worst-case scenario happens (their creator dies, someone tries to mess with their heads and fails in an unlucky way, their control system is interfered with, etc), their basic programming isn't "be a sentient being who is confused" it's "KILL KILL KILL".
That's bad. It's like having a cunningly bound Devil or Demon: clever in the short run, but it'll last forever and will eventually turn on you horribly. And we can't recruit and manage these undead with we do our Devils, because they're not sentient.
As for the smell... Look, embalming fluids exist, but anyone who has done dissections will tell you that corpses always smell. A genuinely odourless corpse doesn't exist, especially if it spends its time outside of a hermetically sealed area with all pests kept out.
It's also a terrible PR move regarding our vassals like Monford and whatnot, and that's my main concern. The previous points are honestly all nitpicks compared to that.