Okay, let's image that I've sent you 100 BTC. Now, can you tell me how exactly you would convert the "money" I've sent you into bread and milk?

Because, most of the time people say that just in the context of the blockchain. In that sense I can also say that you can control vast majority of money by just having knife and glove skins in Steam (for the game Counter Strike). You also can trade/send/receive. But the moment you decide that you want to convert to "food" all sorts of problems arise that are worse than what banks offer.

I'm telling you as a person who received salary in crypto while living under sanctioned country

There is no conversion of money into goods, only exchange of money for goods.

I'll give you some bread and milk for 100 BTC if you want. I'll even fly to your country to personally deliver them to your house.

Yes, you convert them into bread and milk the same way you convert little pieces of paper into bread and milk: You find someone who's willing to give you bread and milk in return for them.