I am a writer and content producer with experience writing for both technical and non-technical audiences. I have worked as a technical writer and manager, a software developer, a marketer, a freelance writer of non-technical things, and a travel photographer. I feel that my range of experiences brings depth and insight to my writing.
I like this explanation of a blockchain: https://www.nerdwallet.com/article/investing/blockchain
I have worked mostly with the BTC blockchain, and have a solid knowledge of Ethereum and other ERC20 coins. My last company covered a wide range of assets including XRP.
Cryptocurrency can reach into many industries, the most obvious being finance and technology.
Having a general understanding of what cryptocurrency/decentralized currency is, how it works, and how it differs from fiat currency is necessary. It is a fast-changing, moving market, so it's helpful to be up on the current crypto "trends", even though they change frequently. If you are writing for an app specific to blockchain technology, then yes, it is necessary to understand how at least the BTC and ETH blockchains operate.
Any of these are fair game. If you are writing for end-users, then it is often important to explain the basics of the blockchain technology and the cryptocurrency ecosystem, since it's often seen as intimidating or misunderstood. There's a lot of basic user education that needs to be done before diving into your particular app's functionality.
If you are writing for developers, then API guides are necessary. Depending on the requirements and function of the API, explanations of blockchain technology/user education aren't always required.
Yes, absolutely. Digital currency in some form or another isn't going anywhere.
I've always found that writing on a topic that you are interested in makes the work much more enjoyable. Cryptocurrency is a fascinating area, always growing and changing with new things to learn. If you are interested in crypto, then finding a writing job where you're immersed in it is a great step for your career and can bring joy to your day-to-day activities.
Don't assume reader knowledge. Cryptocurrency and blockchain technology is unfortunately seen as intimidating to most people. Work extra hard to make your writing fun, interesting, and engaging to the reader.
Be prepared to be constantly learning and changing as the ecosystem and markets grow.
As for documentation managers, the same qualities that make a great documentation manager in other industries apply here. Excite your team, help them grow, and foster an open and communicative environment.