Warning - This article contains minor spoilers for The Mandalorian Season 2.
You just never know when something might come in handy.
For Din Djarin, this wisdom has been put to use several times. It didn't take long for Mando to put his new whistling birds into action in "Chapter 3" when he shot up the Remnant safe house to save the Child. It took even less time for our hero to take his new jetpack for a swing, taking down Moff Gideon's TIE Fighter in the process.
As a bounty hunter, Mando's one and only objective is to make money. Obviously, his priorities changed pretty quickly after we met him, as he's now a decommissioned bounty hunter, but Djarin has taken several jobs since taking Baby Yoda into his care in order to pay for necessities. In "Chapter 11 - The Heiress," it turns out that he already had exactly what he needed...
In The Mandalorian "Chapter 11 - The Heiress," Mando pays the Mon Calamari server with Calamari Flan for information. This currency was obtained by Din Djarin from Greef Karga in "Chapter 1" as remuneration for the introductory mission:
WHAT THIS MEANS
It's always nice to see things previously introduced brought back into the fold. In this case, the Calamari Flan was something that Mando begrudgingly accepted as compensation from Greef Karga early on in the show, and a settlement full of Mon Calamari proved to be the perfect time to spend those credits.
It should be noted that all of the income Mando made during his bounty hunting days went towards his covert's funds, and the Calamari Flan he acquired were presented to the Armorer in the pilot episode. However, what became of those credits was never specified, and it's highly unlikely that Mando would've accepted such an obscure currency while doing odd jobs to keep himself and the Child afloat.
Unfortunately, the Flan proved to be wasted money, as the assistance Mando received in exchange betrayed him. On the other hand, one could argue that it was money well spent, because it inadvertently led Din Djarin to meeting Bo-Katan Kryze and her fellow Nite Owls.
So there you have it. Calamari Flan is the driving heroic force for The Mandalorian's story.