Question: why is diglett wearing a cloth? One; he's underground and therefore doesn't need to cover up, and two; Diglett dong.
I found a higher resolution version that really captures the sheer ungodly abomination in crisp, gaunt horror: https://i.imgur.com/Gsm5vns.png
Question: why is diglett wearing a cloth? One; he's underground and therefore doesn't need to cover up, and two; Diglett dong.
Would you want your dong dragging on subterranean tunnels? No.
He needs it for the situations where he's coming out, for scratching and similar.