The factor is, Din didn’t understand the weapon’s particular significance. So his new-ish ally Bo-Katan Kryze—the sister of Clone Wars’ Duchess Satine, the previous ruler of Mandalore, and herself the temporary chief of the Mandalorian resistance earlier than the Empire ravaged the planet—is livid that he has it, as a result of the one approach she will now honorably purchase it herself is to defeat him in ritual fight, which Din does not wish to occur. So her personal plans to return to Mandalore and rule her individuals have been upended.
Additionally, he retains slicing himself open attempting to make use of a lightsaber he doesn’t know tips on how to use, so there’s additionally that. He’s not even proud of himself!