Sadly, I have first hand exeperience working on software where the devs clearly 1) did not use the software they created, 2) did not fully understand the purpose of the software
At my first job I built a system to track charitable donations by local bank branches for the banks lawyers. I couldn't even understand most of the status drop downs I built as they were just line numbers in IRS forms (eg 1040 13b). The PM on the project was barely doing any better.
But when we were done the lawyers all agreed that it was 1000 times better than the Excel spreadsheet that the lawyers themselves had built and were passing around between offices.
Would it have turned out better if I'd been a tax attorney before taking on the gig, I'm sure. But you can still get results without the deep domain knowledge residing in the programmer's head.
We had an extremely happy client, who used this thing extensively in his own consulting business. None of the developers could tell you how the software was to be used, beyond: “It stores data in a tree like structure with three node types”.
Do you think that devs from FAANG, MS, Adobe, open-source projects, etc really have no idea what they are programming? Unless software dev is like an iceberg where there is much much more unseen than seen???