Probably good marketing, since it seems to make money and generate buzz, but in my mind, also probably bad engineering.
It's not a library, no one is supposed to drop it into their codebase like a C header, so keeping everything in a single file gives no objective advantage over using multiple files, even with a similar sized codebase.
It's not a library, no one is supposed to drop it into their codebase like a C header, so keeping everything in a single file gives no objective advantage over using multiple files, even with a similar sized codebase.