It depends what you use it for. I worked on a interbank messaging platform that normalised everything into a series of standard xml formats, and then used xslt for representing data to the client. Common use case - we could rerender data to what a receiver’s risk system were expecting in config (not compiled code). You could have people trained in xslt doing that, they did not need to be more experienced developers. Fixes were fast. It was good for this. Another time i worked on a production pipeline for a publisher of education books. Again, data stored in normalised xml. Xslt is well suited to mangling in that scenario.

That's funny, I would reverse those. I loved XSLT though it took me a long time for it to click; it was my gateway drug to concepts like functional programming and idempotency. XPath is pretty great too. The problem was XML, but it isn't inherent to it -- it empowered (for good and bad) lots of people who had never heard of data normalization to publish data and some of it was good but, like Irish Alzheimer's, we only remember the bad ones.