Seems a bit odd.
Shultze-mueller-gambit

Even in slow and correspondance games Black should be very careful in order to counter this opening correctly. Game can quickly become dangerous.

Sacking a piece on the 4th move without anything tangible? You're really counting on your opponent screwing up, I wouldn't play it at high level.

At The Unsound Openers we play it in TMs and even in vote chess, against groups that have 2000+ rated players participating.
The Halloween Gambit (also known as the Müller–Schulze Gambit or Leipzig Gambit) is an aggressive chess opening gambit in which White sacrifices a knight early-on for a single pawn. The opening is an offshoot of the normally staid Four Knights Game and is defined by the moves: