Awesome! Nothing wrong with self-hosting if that's what you like to do, or want to learn.
It might not be the best option for small businesses with limited time, since webpages are so cheap these days. Paying a vendor $20/mo is much less cost than paying an employee for even an hour. I've seen too many "orphaned" sites to recommend DIY webpages to regular small businesses by default anymore, where simpler vendor solutions exist. But that's just one use case.
On the other hand, many people here, myself included, got started in our careers by setting up similar self-hosted options and learning about the technologies. Plus, as you said, for certain use cases (documentation) there are certainly more specialized options available than what Squarespace would give you.
Choosing the right tools for the job is half the fun!
It might not be the best option for small businesses with limited time, since webpages are so cheap these days. Paying a vendor $20/mo is much less cost than paying an employee for even an hour. I've seen too many "orphaned" sites to recommend DIY webpages to regular small businesses by default anymore, where simpler vendor solutions exist. But that's just one use case.
On the other hand, many people here, myself included, got started in our careers by setting up similar self-hosted options and learning about the technologies. Plus, as you said, for certain use cases (documentation) there are certainly more specialized options available than what Squarespace would give you.
Choosing the right tools for the job is half the fun!