Firesnap Cookie has a restriction of being unable to target or affect units that are channeling a spell.

Now, this is a great way to prevent Snapfire from accidentally (or intentionally) interrupting allies. BUT, this restriction should not apply to self-casts.

Why? Because casting it on your self is an active decision you make yourself. You intent to cancel your channeling in order to hop away. Right now, you first have to cancel your channeling in other ways and then cast the cookie on you, which costs time, and may not be obvious to players who don't know about the channel restriction yet.