Being two mana is a drawback compared to the other two, but being able to fight at instant speed opens up the possibility of some big blowouts (and reduces the chances of your creature getting killed in response to the fight spell since you have more control over the timing), and drawing a card if you win the fight is really powerful
In this match-up I had a great board position and my opponent gave up.
Simba, the other main option in the pack, is one of the best commons in the set
If you play commander, a Revised edition Sol Ring will stand out at the table
5 mana is perfectly accessible for a casting cost, and with a way to move your permanents out of harms way or cast them from suspend or the graveyard, it has almost no equal when it comes to facilitating the end of the game
If you want that cheap-but-high-stakes extra turn spell, you have better options