This is from a video teaching Japanese meaning from Super Mario RPG. Source: https://youtu.be/1LMxshr0BE4?t=497
The context is: Mario and Mallow(little white puff ball) are trying to get a coin back from Croco(purple guy). Croco has been punched by Mallow, then basically says Mario and Mallow can have the coin back.
The part I am confused about is 一文にもならない. The creator of the video says it means 'worthless'.
How does the video creator know this? I cannot find any meaning of this online so I just want to be sure this is correct. Thank you.