Because Ghyrson inflicts the damage, his plinks are an inevitable route to victory via Commander damage
In most cases, I will be referencing CGCs standards in this guide
It is not all upside, by using the enchantment ramp over creatures you lose some consistency on your Overrun kills via Garruk and Craterhoof which are your main routes to victory
If the exiled permanent was a commander, the tokens won't be commanders
Considering that exiling things is pretty easy to do nowadays, Ketramose can easily turn into a card advantage engine
When you can play it the Cloud brings awesome power offering a pretty good representation of a Mind Twist, an Armageddon, a Wrath of God or a Fireball, often a couple of those things and almost always far worse for your opponent than you