The short answer is that a "narrow bank" is not really a bank, and is not performing the same functions as a bank. In fact, they are basically just like stablecoin issuers, in that they accept deposits and then buy Treasuries with them 1:1. The entire power of the modern banking system (and it's very important to think about it as a system, and not just isolated individual banks) is its ability to create credit money through the issuance of debt. A "narrow bank" is basically just a pass-through entity for people to invest in Treasuries.Interesting, if its impossible, why won't the Fed grant a master account? The Narrow bank and Custodia bank would be too unprofitable? Haha.
Okay, so now you're just making up your own terminology in the vein of Saylor. Why not go further and just say that Bitcoin adds +5 Strength or grants you +5 Mana? Like, what are we doing here? Words have meaning, and if you just arbitrarily redefine them to obfuscate your position then intelligent discussion becomes impossible. Yield, in the financial definition, specifically refers to the income generated by an investment. This is typically in the form of rents, dividends or interest payments. It has nothing to do with future price appreciation. Yield is expected to be regular and ongoing.Bitcoin DOES HAVE A YIELD, just not in bitcoin but in dollars.
BITCOIN DOES NOT PRODUCE YIELD. Period. The only way to make money from Bitcoin is by selling it to someone else for more than you paid. Holding Bitcoin does not provide you more Bitcoin, nor does it provide you more dollars. The idea that Michael Saylor is "generating yield" from Bitcoin is fraudulent, at best illusory. In essence, he is taking $100 dollars from people, giving them $11 back a year later, and using the $89 to buy more Bitcoin. He has no means of generating dollar income except by selling more future dollar obligations. This is the exact mechanism of operation of a Ponzi scheme: paying off existing holders with money taken from new buyers.