This is only useful if you have less than ~3000SP and want new account creation tokens. 

You only need about 3000SP worth of Resource Credits to create a single Steem Account Creation Token. If you're considering delegating more than this amount, its probably better to hold onto your own Steem Power and generate the account creation tokens yourself using Steemworld.org 

I've added this comment in the interests of transparency. 

In regards to the invite token, I am assuming they can be traded in quantities only larger than 1? If this isn't the case, I could see a lot of "invite dust" distributed which isn't a fantastic experience for delegators, and I would encourage this information to be made available to the community.