Also keep in mind that Microsoft hasn't actually given OpenAI $13 Billion because much of that is in the form of Azure credits.
So this could end up being the cheapest acquisition for Microsoft: They get a $90 Billion company for peanuts.
[1] https://stratechery.com/2023/openais-misalignment-and-micros...
To be clear, these don't go away. They remain an asset of OpenAI's, and could help them continue their research for a few years.
Crypto in general you could maybe get $200M worth from $1B in credits. You would likely tank the markets for mineable currencies with just $1B though let alone $13B