The RAF thing, is designed for me to get a friend into the game.
A boxer will often RAF to themselves, but the program was designed to get others into the game.

It is perfectly fine for me to recruit a different person, link their account to mine, and for us to level a lot quicker together.
It is perfectly fine for that person to use the granted levels to give me my bonus.
It is also fine to get my free month, when they pay for their first month.
And I get the RAF mount, when they pay for their second month of the game.

Basically, the benefits Blizzard gives you are fine, but nothing beyond that.
It isn't okay to receive any monetary amount, just what Blizzard gives.

You can buy an account as a gift, but once someone owns it, it is their account and becomes non-transferable.