Steeminvite is for creating new accounts on Steemit safe and fast (without having to wait to be accepted) - that is if for example your friend wishes to make an account on Steemit but doesn't want to wait for a week or even more, you can make one for them.

BUT to make one through steeminvite, you need to have an extra 0.100 SBD and 14.500 SP as the account creation fee. The SP will be delegated to the new account and you may undelegate any time, although it would be nice to let the new user gain 14.500 SP of their own beforehand.