A better way to put it is that these things do have value to the customer, the customer just doesn't have a way to understand how the work you're doing provides value because it's the part of the product you don't see. If you clean up technical debt, improve test coverage, improve your deployment systems, etc, it doesn't change the immediate customer experience in a meaningful way, but it does allow you to deliver the changes that customers do see faster and with fewer risks.

This quote makes it seem like the work is self-indulgent, and I have seen that happen sometimes, but it's not half of what we do.