The mats for this are somewhat expensive. About what it would have been to build a jeeves back in the day. I don't have a problem with that. It is a max level reusable item that does offer benefits to those that use it..
But let's have a rational conversation about those benefits.
The profession levelling Fire Spirit won't help the engineer who crafted him. The engineer already has 600 engineering. If the engineer is a miner it is likely also maxed. I suppose it might help another profession that isn't mining. Definately would be useful in future expansions.
Also, free engineering mounts and pets for everyone! Wait a minute... Isn't that a source of income for engineers? Why would I set up a mount and pet vending machine in a place where people could find it. I don't care how low the drop rate is.
It is a cool idea and fun to make new friends and help guildies and whatnot. I just don't really see the benefit for the engineer.